INNKALLING TIL MØTE I FORSKNINGSNEMNDA

Transcription

INNKALLING TIL MØTE I FORSKNINGSNEMNDA
FON- SAK
NR :
U NIVERSITETET FOR MILJØ - OG
61/2010
BIOVITSKAP
F ORSKINGSNEMNDA
S AKSANSVARLEG : R AGNHILD S OLHEIM
S AKSBEHANDLAR : Å GOT A AKRA
A RKIVSAK NR :
Sak 61/2010
”Open Access”-publisering ved UMB
Dokument:
a) Saksframlegg
b) Vedlegg:
1. ”Forskningsrådets prinispper for Open Access”
2. BioMed Central-tidsskrift, PLoS-tidsskrift
3. Gargouri Y, Hajjem C, Larivière V, Gingras Y, Carr L, et al. 2010 Self-Selected or
Mandated, Open Access Increases Citation Impact for Higher Quality Research.
PLoS ONE 5(10): e13636. doi:10.1371/journal.pone.0013636
4. Oversikt over OA-publisering ved UMB dei siste åra blir lagt fram i møtet
Forslag til vedtak:
1. Forskingsnemnda tilrår at UMB etablerer avtalar med dei mest relevante forlaga (xx, xy,) for
Open Access- publisering med mål om kostnadseffektiv publisering i opne tidsskrift.
2. Forskingsnemnda tilrår at det blir innført ei insentivordning som kan motivera til arkivering
og tilgjengeleggjering av forskingsresultat gjennom Brage.
Ås, 02.11.2010
Ragnhild Solheim
Forskingsdirektør
U NIVERSITETET FOR MILJØ - OG BIOVITSKAP
F ORSKINGSNEMNDA
M ØTEDATO 09.11.2010
SAKSFRAMLEGG
FON 61/2010
1
Bakgrunn
I UMB-strategien, står det at UMB skal ”synliggjøre forskningsresultatene gjennom blant annet
’Open Access’” og forskingsmeldinga ”Klima for forskning” seier: ”Prinsipielt mener regjeringen at all
offentlig forskning bør være åpent tilgjengelig, så sant ikke andre hensyn hindrer det”. Forskningsrådet stiller
også krav om at at fagellevurderte publikasjonar blir leverte til dei institusjonelle arkiva, dersom
resultata i publikasjonane kjem frå arbeid som er finansiert av NFR.
Saka blir lagt fram for FoN nå for å få ein diskusjon om korleis UMB kan oppnå auka
synleggjering av forskingsresultata våre gjennom Open Access (OA). Dersom UMB skal oppnå
auka synleggjering av forskinga gjennom open access, trengst strategiar for publisering som
fremmar open publisering.
Der er to måtar å oppnå open tilgang til forskingsresultat: a) eigenarkivering i opne
publiseringsarkiv og b) publisering i opne, elektroniske tidsskrift:
Eigenarkivering i opne publiseringsarkiv: Eigenarkivering er eit middel for auka tilgangen til
forskingsresultat. Universiteta har etablert eigne arkiv for OA-publisering. Ved UMB er det Brage
som blir brukt, og f.o.m 2010 blir alle masteroppgåver tilgjengeleggjort i fulltekst her. Det er
førebels frivillig for ein forskar å avlevera publikasjonar for OA-publisering gjennom dei opne
arkiva. Per i dag er det berre masteroppgåver som er arkivert i Brage UMB. Di fleire
publikasjonar som blir opent tilgjengelege på internett, anten gjennom Brage eller andre kanalar,
di meir synleggjort blir forskingsinstitusjonen. Likevel, tilgjengeleggjering av fagfellevurderte
publikasjonar gjennom opne arkiv (som Brage) medfører ein del ekstra arbeid, først og fremst
knytt til klarering av copyright og versjonshandtering (kva for versjon av ein publikasjon blir
godtatt for OA-publisering av forlaget?), og dersom ein ønskjer at tilgjengeleggjering av
publikasjonar gjennom opne arkiv skal vera standard, kan det vera nødvendig med
insentivordningar som motiverer til at forskarar legg ut publikasjonar med open tilgang.
(Høgskolen i Oslo har innført eit internt belønningssystem som insentiv til open publisering.)
Det kan også vera nødvendig med ein sentral teneste som sørgjer for klarering av fagfellevurderte
publikasjonar for arkivering og tilgjengeleggjering.
(Der har også vore diskusjonar om der er ein siteringsfordel ved open access-publiserig. Ein nyleg
publisert artikkel (vedlegg 3) samanliknar sitering av eigenarkiverte og ikkje-eigenarkiverte artiklar
i dei same tidsskrifta, og det viser seg at eigenarkivering gir ein siteringsfordel, og fordelen er
størst for dei beste (nyttigaste) artiklane. Dette kan vera eit godt argument for å motivera til
eigenarkivering av fagfellevurderte publikasjonar.)
Publisering i opne, elektroniske tidsskrift: Publisering i opne, elektroniske tidskrift har blitt vanleg
dei siste åra, mykje på grunn av at mange av dei opne tidsskrifta er internasjonalt prestisjetunge
og har same gode kvalitetssikringssystem (fagfellevurdering osb.) som ordinære, trykte tidsskrift..
I dag finst det over 5500 vitskaplege OA-tidsskrift (sjå oversikt her: http://www.doaj.org/,
Directory of Open Access Journals). Der finst OA-tidsskrift innanfor nær sagt alle fagområde.Ein
ulempe med publisering i opne tidskrift er publiseringavgiftene. Avgiftene for å publisera i ein del
open access-tidsskrift er svært høge. Gjennom avtalar med forlaga kan ein likevel redusera
publiseringsavgiftene. Nokre døme på korleis ein kan redusera avgiftene ved publisering i opne
tidsskrift følgjer:
Universiteta i Oslo, Bergen, Trondheim og Tromsø har nyleg forhandla fram ein avtale (eitt-årig
prøveprosjekt) om kjøp av elektroniske bøker innanfor alle dei 13 emnepakkane Springer-forlaget
har. (UMB testar for tida ut e-bøkene frå Springer: http://www.umb.no/biblioteket/artikkel/eU NIVERSITETET FOR MILJØ - OG BIOVITSKAP
F ORSKINGSNEMNDA
M ØTEDATO 09.11.2010
SAKSFRAMLEGG
FON 61/2010
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boker-fra-springer-2). I denne avtalen inngår også gratis publisering i Springer Open Choice, som
er Springers portefølje av OA-tidsskrift. Springer Open Choice omfattar ca 1000 OA-tidsskrift og
av desse er ca. 800 godkjende publiseringskanalar. Gjennom avtalen om gratis publisering i
Springer Open Choice-tidskrift, blir artiklane publiserte på tradisjonelt vis for abonnentar og
gjennom open publisering, utan publiseringskostnaden som OA til vanleg medfører. Ordinær
publiseringskostnad i eit Springer Open Choice-tidsskrift er USD 3000 (2000 Euro) per artikkel.
Føremålet med prosjektet ved dei fire breiddeuniversiteta er å kartleggja i kva for grad forskarane
er interesserte i å velja OA-publisering når vilkåra elles er dei same som for publisering i tidsskrift
med lisensiert tilgang. Prøveprosjektet vil sjølsagt bli evaluert, og målet er å komma fram til ein
økonomisk modell for OA-publisering som kan vera akseptabel både for universiteta og
utgivaren.
UMB var ikkje førespurt om å vera med i avtalen med Springer som dei fire breiddeuniversiteta
nå er med i. Forskingsavdelinga har bede biblioteket undersøkja kostnadene med ein liknande
avtale med Springer for UMB. I skrivande stund kjenner me ikkje kostnadene med ein kombinert
e-bok/Springer Open Choice-avtale.
BioMed Central er eit forlag som berre publiserer OA-tidsskrift, innanfor biologi og biomedisin
(sjå vedlagt oversikt over tidsskrift). BioMed Central er nå kjøpt opp av Springer, og eit alternativ
til ein avtale med Springer (e-bøker + Springer open Choice), kan vera medlemsskap i BioMed
Central. Eit slikt medlemsskap vil omfatta alle tidskrift frå BioMed Central, samt Springer Open
Choice. Medlemsavgift til BioMed Central er basert på kor mange artiklar ein har publisert
foregåande år, og ein betaler inn eit forskott (2008: 15000 Euro) og får deretter rabatt på
publisering av artiklar. Dette synest likevel å vera ein relativt dyr avtale, og alternative former for
medlemsskap vera meir aktuelle: UiB og UiT har avtale om ”supporter membership” med BMC.
Denne avtalen inneber at forskarar ved desse institusjonane får 15 % rabatt på
publiseringsavgifta, gitt at institusjonen betaler ei fast årleg avgift. For UMB vil ei slik avgift vera
på €4,004. Standard publiseringsavgift hos BioMed Central er (€1135/US$1600 per artikkel, men
i nokre journalar (t.d. Genome Biology) er avgifta €1740/US$ 2455 per artikkel.
Eit anna relevant OA-forlag er PLoS (Public Library of Science). PLoS-journalane (7 stk) er etter
kvart blir internasjonalt svært anerkjende journalar. (I Forskdok har UMB-forskarar registrert 28
publikasjonar i PLoS-journalar sidan 2008.) Publiseringavgifta i PLoS-journalar varierer frå
US$1350 (PLoS One) til US$2900 (PLoS Biology) per artikkel. Også PLoS tilbyr reduserte
publiseringsavgifter til forskarar ved medlemsinstitusjonar som betaler ei fast årleg avgift. For
UMB vil den årlege avgifta til PLoS vera på US$ 2000 og gir 10 % rabatt på publiseringsavgifta
per artikkel.
Alle BMC- og PLoS-journalar er fagfellevurderte og kvaliteten er fullt på høgd med det ein finn
hos vanlege forlag. Meir bruk av denne type open publisering er derfor med på å sikra at OApublisering ikkje blir ”annanrangs” publisering, som har vore nemnt som ei mogeleg ulempe med
OA.
(Andre kjende forlag som er relevante når det gjeld OA-publisering er Elsevier og Hindawi
Publishing Corporation.)
Det er ønskjeleg om FoN drøftar:
– Kva må til for at forskarar ved UMB skal ta i bruk Brage for open publisering og dermed
bidra til å synleggjera forskinga ved UMB meir? Kva for insentivordningar er naudsynte?
– Bør UMB etablera avtalar med OA-forlag for å redusera publiseringskostnadene og
motivera til publisering i anerkjende OA-kanalar? Kva for kvalitetskriterium bør liggja til
U NIVERSITETET FOR MILJØ - OG BIOVITSKAP
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M ØTEDATO 09.11.2010
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grunn for forlag som UMB ønskjer å inngå avtale med? Kva for kriterium bør liggja til
grunn når det gjeld rettar og vidare bruk av publikasjonar?
Kor skal (budsjett)ansvaret vera – institutta eller biblioteket? Kan eit publiseringfond vera
ein mulighet for UMB? (Ein del institusjonar har oppretta sentrale publiseringsfond som
sikrar at publiseringsavgifter til opne tidsskrift blir dekka.)
Forskingsdirektørens vurdering
Open Access-publisering bidrar til å gjera forskinga vår synleg og tilgjengeleg nasjonalt og
internasjonalt. Open tilgang til forskingsresultat er i samsvar med samfunnsrolla UMB har.
Likevel, det er svært viktig at tilgang til forskingsresultat gjennom Open Access er i tråd med vår
strategi om at forskinga skal ha høg kvalitet. Det må ikkje vera tvil om at materiale som blir lagt
ut som open access held høg vitskapleg kvalitet, og det er da naturleg at ein konsentrerer
innsatsen på open publisering mot fagfellevurderte publikasjonar.
FoN bør drøfta korleis UMB kan arbeida for å auka synleggjering av forskinga vår gjennom open
publisering. Vidare bør FoN drøfta om UMB bør etablera avtalar om reduserte
publiseringsavgifter i OA-tidsskrift. Dersom dette er aktuelt, må ein årleg setja av tilstrekkeleg
midlar til dette, og ein må ha ei meining om kor budsjettansvaret skal vera, dvs korleis skal UMBforskarar få dekka publiseringsavgifter? Mange har prosjektmidlar som kan dekka dette, men
dette gjeld ikkje alle. (Forskingsavdelinga har ikkje oversikt over kor store publiseringsutgifter
institutta har i dag.)
Dersom det ikkje er aktuelt å inngå avtalar om OA-publisering med anerkjende forlag som dei
som er nemnde over, må ein drøfta korleis ein skal oppnå meir OA-publisering av høg
internasjonal kvalitet på anna vis.
U NIVERSITETET FOR MILJØ - OG BIOVITSKAP
F ORSKINGSNEMNDA
M ØTEDATO 09.11.2010
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Forskningsrådets prinsipper for åpen
tilgang til vitenskaplig publisering
Universitetet for miljø- og biovitskap
Forskingsnemnda
Møtedato 09.11.2010
Vedlegg 1
FoN-sak 61/2010
2
Forskingsnemnda
Møtedato 09.11.2010
© Norges forskningsråd 2009
Norges forskningsråd
Postboks 2700 St. Hanshaugen
0131 OSLO
Telefon: 22 03 70 00
Telefaks: 22 03 70 01
[email protected]
www.forskningsradet.no/
Publikasjonen kan bestilles via internett:
www.forskningsradet.no/publikasjoner
eller grønt nummer telefaks: 800 83 001
Universitetet for miljø- og biovitskap
Vedlegg 1
FoN-sak 61/2010
3
Forskningsrådets prinsipper for åpen
tilgang til publisering
1) Målsetting
Det er en viktig forskningspolitisk målsetting at resultatene av offentlig finansiert forskning skal være
offentlig tilgjengelige. Vitenskapelig publisering som bygger på FoU-prosjekter som er helt eller
delvis finansiert av Forskningsrådet, skal i størst mulig grad være åpent tilgjengelig for alle
interesserte. For å oppnå dette skal Forskningsrådet bidra til at det potensialet for formidling og
kvalitetssikring av forskningsresultater som ligger i digitale medier og infrastruktur blir utnyttet til
fulle.
Merknader
Open Access – åpen tilgang til vitenskapelig publiserte artikler – er en målsetting om en åpen, og
kvalitetssikret kilde til kunnskap. De siste årene har Open Access fått aktualitet fordi enkelte
internasjonale tidsskriftforlag har kommet i en monopolsituasjon, noe som har ført til en sterk vekst i
kostnadene til tidsskriftabonnementer. Dette har igjen satt institusjonsbibliotekenes budsjetter under
sterkt press.
Open Access dekker imidlertid også andre viktige forskningspolitiske behov gjennom å:
a) Øke den faglige kvaliteten ved at flere enkelt kan kommentere og bygge videre på publiserte
forskningsresultater
b) Ved at næringsliv og annen virksomhet enkelt får tilgang til publiserte forskningsresultater
c) Ved at myndigheter og forvaltning får kunnskap om forskningsresultater
d) Ved å lagre et ubegrenset antall digitale kopier av artikler, sikre tilgang til dagens publiserte
forskningsresultater for framtiden
e) Ved å gi forskere ved lite bemidlede institusjoner, ikke minst i utviklingsland, tilgang til de
nyeste forskningsresultatene.
Det er i hovedsak to innfallsvinkler til åpen tilgang til vitenskapelig publiserte artikler:
1) Egenarkivering av allerede publiserte artikler i institusjonelle eller fagspesifikke digitale arkiv
med ubegrenset offentlig tilgang.
2) Fagfellevurderte elektroniske tidsskrift som er vederlagsfritt og allment tilgjengelige (Open
Access-tidsskrift). Utgivelseskostnadene ved Open Access-tidsskrift dekkes på andre måter
enn gjennom abonnement, som regel ved at forfatter betaler for å publisere.
De to innfallsvinklene til Open Access refererer til to forskjellige forretningsmodeller for
vitenskapelig tidsskriftpublisering. Egenarkivering innebærer ingen vesentlige utfordringer for dagens
abonnementsbaserte system, men kan forventes å presse ned forlagenes priser fordi artikler etter en tid
(normalt inntil seks måneder) er gratis tilgjengelige. Open Access-tidsskrift utfordrer på sin side den
etablerte abonnementsmodellen, og kan gi strukturelle konsekvenser det i dag er vanskelig å forutse.
For eksempel er spørsmålet om hvordan forfatterbetaling skal organiseres og finansieres på en
bærekraftig måte, uavklart.
Open Access er ikke begrenset til vitenskapelige tidsskriftsartikler. Antologiartikler og monografier er
eksempler på andre fagfellevurderte publikasjoner som kan sees i et Open Access-perspektiv.
Tidsskriftsartikler er imidlertid den dominerende publiseringsformen – internasjonalt og på tvers av
fagfelt. Det er derfor foreløpig hensiktsmessig å avgrense Forskningsrådets Open Access-prinsipper til
denne publiseringsformen.
Universitetet for miljø- og biovitskap
Forskingsnemnda
Møtedato 09.11.2010
Vedlegg 1
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Norske forskere har lenge kunnet bidra til Open Access gjennom å deponere egne vitenskapelige
artikler i institusjonelle og fagspesifikke elektroniske arkiv. Til tross for oppfordringer til å
egenarkivere, har få forskere benyttet seg av denne muligheten. Internasjonal erfaring tyder også på at
oppfordring til egenarkivering gir få resultater, mens krav fører til stor oppslutning blant forskere. Å få
den viktigste brukergruppen, forskerne, til å ta i bruk egenarkivering, framstår som en avgjørende
suksessfaktor.
2) Forskningsrådets krav til åpen tilgang til vitenskapelig
publisering
De samfunnsmessige fordelene knyttet til åpen tilgang til vitenskapelig publisering er betydelige.
Forskningsrådet vil derfor stille krav om at fagfellevurderte vitenskapelige artikler som bygger på
forskning helt eller delvis finansiert av Forskningsrådet skal egenarkiveres i egnede arkiv der hvor
slike finnes. Krav om slik arkivering må likevel ikke komme i konflikt med forfatters akademiske og
juridiske rettigheter.
Merknader
Forskernes rett til selv å velge publiseringskanal for egne vitenskapelige resultater er et viktig aspekt
ved den akademiske friheten. Men forskere har også en akademisk forpliktelse til å publisere på en
slik måte at fagfellesskapet og allmennheten får en tilfredsstillende tilgang til disse resultatene.
Prinsippet om den enkelte forskers frihet til å velge kanal for publisering av sine forskningsresultater
kan utfordres på to måter gjennom krav om Open Access:
1) Krav om egenarkivering kan begrense muligheten til å publisere i tidsskrift som ikke godtar
dette. De fleste norske og internasjonale vitenskapelige tidsskrift godtar imidlertid i dag
egenarkivering. Krav om egenarkivering fra stadig flere forskningsinstitusjoner og -finansiører
gjør at det er et tidsspørsmål før dette er vanlig praksis. I de tilfeller hvor egenarkivering
likevel ikke er tillatt, bør Forskningsrådet kunne godta unntak fra kravet om egenarkivering.
2) Open Access-publisering som finansieres ved forfatterbetaling kan innebære nye økonomiske
og administrative begrensninger. Det kan for eksempel være uheldig dersom
forskningsmiljøene får beslutningsmyndighet over hvem som skal motta midler til å publisere
og dermed faktisk får publisert. Forskningsrådet bør derfor være forsiktig med å etablere
insentiver som bidrar til å endre grunnleggende publiseringsmønstre, før det foreligger
tilstrekkelig kunnskap om konsekvensene av forfatterfinansiert publisering.
Når Forskningsrådet pålegger forskere å lagre opphavsrettslig materiale i institusjonelle arkiv, må
Forskningsrådet være sikker på at slik arkivering ikke bryter med forfatters og utgivers
opphavsrettslige rettigheter til dette materiale. Dette gjelder blant annet for sekundærbruk av publisert
materiale, som digitale kompendier til bruk i undervisning. UHR og rettighetsorganisasjonene er i
gang med forhandlinger om bruk av digitalt materiale ved institusjonene. En framtidig avtale vil
sannsynligvis avklare opphavrettslige sider ved sekundærbruk av materiale fra digitale arkiv og
Forskningsrådet vil ta hensyn til en slik avtale i de krav som stilles til egenarkivering.
3) Egenarkivering: Infrastruktur og brukerperspektiv
Vitenskapelige tidsskriftsartikler som faller innenfor kravene i punkt 2 skal arkiveres i et åpent
elektronisk arkiv (repository), enten ved den institusjonen forskeren er tilknyttet eller i et fagspesifikt
arkiv. Normalt skal en ”post-print-versjon” av artikkelen arkiveres. Dersom forfatteren publiserer i et
tidsskrift som ikke tillater slik arkivering og ikke har mottatt slik tillatelse fra utgiver etter å ha
forespurt om dette, kan vedkommende få fritak fra krav om egenarkivering.
Universitetet for miljø- og biovitskap
Forskingsnemnda
Møtedato 09.11.2010
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Merknader
Den tekniske og administrative infrastrukturen for egenarkivering er i stor grad på plass ved norske
utdannings- og forskningsinstitusjoner, gjennom blant annet DUO ved UiO og BIBSYSs Brageløsning. Helseforetakene, på sin side, har utviklet et felles system (HERA), mens det innenfor
instituttsektoren er varierende dekning. Det finnes også internasjonale fagspesifikke åpne arkiv
innenfor enkelte forskningsfelt, for eksempel UK PubMed Central. Dersom dette er arkiv som øker
synligheten til publikasjonene eller er foreskrevet som pliktarkiv av andre oppdragsgivere, bør
Forskningsrådet oppfordre forskere til å benytte disse.
Brukervennlighet er en viktig faktor for å sikre at forskere egenarkiverer uten å føle det som en ekstra
arbeidsbyrde. En arbeidsgruppe nedsatt av Kunnskapsdepartementet har nylig levert forslag til en
felles database for vitenskapelig publisering innenfor et nasjonalt system for forskningsinformasjon.
Arbeidsgruppens anbefalinger er samlet i rapporten Norsk vitenskapsindeks (NVI) (NIFU-STEP,
rapport 33/2008). Bakgrunnen for arbeidet er behovet for å samle publiseringsdata fra helseforetakene,
UH- og instituttsektoren i ett register. Det er mulig å videreutvikle NVI til også å kunne laste opp
fulltekstartikler til institusjonelle arkiv, noe som vil forenkle arbeidet med egenarkivering betraktelig.
En slik bruksmåte vil imidlertid avhenge av hvilke oppfølging rapportens anbefalinger får i
departementet.
En slik videreutvikling av NVI bør også gi forskere informasjon om juridiske rettigheter de har i
forhold til opphavsrett, og om hvilken versjon av artikkelen de kan laste opp. Forskningsrådet og
andre institusjoner som stiller krav om egenarkivering, må likevel forventes å gi veiledning om hvilke
rettigheter forfattere har i forbindelse med egenarkivering.
4) Samarbeid og råd
Open Access er i kontinuerlig utvikling og kan på sikt føre til store endringer i publiseringsmønster og
-praksis innenfor forskning og akademia. Det er viktig at Forskningsrådets prinsipper reflekterer denne
utviklingen, og kan tilpasses dersom omstendighetene krever det. For å sikre at prinsippene til enhver
tid bidrar til målsettingen om åpen tilgang til vitenskapelig publisering, skal Forskningsrådet ha en god
dialog om prinsippene med relevante institusjoner og samarbeidspartnere.
Merknader
Forskningsrådet skal gi forskningspolitiske råd til myndighetene. Kunnskapsdepartementet har i brev
av 2. juni 2008 bedt Forskningsrådet og UHR om gi råd om tiltak som kan fremme egenarkivering og
annen Open Access-publisering. Departementet ber spesielt om en vurdering av om det bør stilles krav
om obligatorisk egenarkivering av offentlig finansiert forskning, samt hvilke juridiske, teknologiske,
kommunikasjonsmessige, økonomiske, administrative og evt. andre konsekvenser dette vil medføre.
Forskningsrådets tilbakemelding til departementet er utformet i overensstemmelse med prinsippene for
åpen tilgang til vitenskapelig publisering.
Universitetet for miljø- og biovitskap
Forskingsnemnda
Møtedato 09.11.2010
VEDLEGG 2
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Bio Med Central - journals
(see also: Chemistry Central journals PhysMath Central journals)
AIDS Research and Therapy
Acta Veterinaria Scandinavica
Algorithms for Molecular Biology
Allergy, Asthma & Clinical Immunology
Alzheimer's Research & Therapy
Annals of Clinical Microbiology and
Antimicrobials
Annals of General Psychiatry
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Self-Selected or Mandated, Open Access Increases
Citation Impact for Higher Quality Research
Yassine Gargouri1, Chawki Hajjem1, Vincent Larivière2, Yves Gingras3, Les Carr5, Tim Brody5, Stevan
Harnad4,5*
1 Institut des Sciences Cognitives, Université du Québec à Montréal, Montréal, Québec, Canada, 2 Observatoire des Sciences et des Technologies, Université du Québec à
Montréal, Montréal, Québec, Canada, 3 Canada Research Chair in the History and Sociology of Science, Université du Québec à Montréal, Montréal, Québec, Canada,
4 Canada Research Chair in Cognitive Sciences, Université du Québec à Montréal, Montréal, Québec, Canada, 5 School of Electronics and Computer Science, University of
Southampton, Southampton, United Kingdom
Abstract
Background: Articles whose authors have supplemented subscription-based access to the publisher’s version by selfarchiving their own final draft to make it accessible free for all on the web (‘‘Open Access’’, OA) are cited significantly more
than articles in the same journal and year that have not been made OA. Some have suggested that this ‘‘OA Advantage’’
may not be causal but just a self-selection bias, because authors preferentially make higher-quality articles OA. To test this
we compared self-selective self-archiving with mandatory self-archiving for a sample of 27,197 articles published 2002–2006
in 1,984 journals.
Methdology/Principal Findings: The OA Advantage proved just as high for both. Logistic regression analysis showed that
the advantage is independent of other correlates of citations (article age; journal impact factor; number of co-authors,
references or pages; field; article type; or country) and highest for the most highly cited articles. The OA Advantage is real,
independent and causal, but skewed. Its size is indeed correlated with quality, just as citations themselves are (the top 20%
of articles receive about 80% of all citations).
Conclusions/Significance: The OA advantage is greater for the more citable articles, not because of a quality bias from
authors self-selecting what to make OA, but because of a quality advantage, from users self-selecting what to use and cite,
freed by OA from the constraints of selective accessibility to subscribers only. It is hoped that these findings will help
motivate the adoption of OA self-archiving mandates by universities, research institutions and research funders.
Citation: Gargouri Y, Hajjem C, Larivière V, Gingras Y, Carr L, et al. (2010) Self-Selected or Mandated, Open Access Increases Citation Impact for Higher Quality
Research. PLoS ONE 5(10): e13636. doi:10.1371/journal.pone.0013636
Editor: Robert P Futrelle, Northeastern University, United States of America
Received January 3, 2010; Accepted September 29, 2010; Published October 18, 2010
Copyright: ß 2010 Gargouri et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Funding: Social Science and Humanities Research Council, Monitoring, Measuring and Maximizing Research Impact, and Canada Research Chair in Cognitive
Sciences. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing Interests: The authors have declared that no competing interests exist.
* E-mail: [email protected]
Hence OA is not just about public access rights or the general
dissemination of knowledge: It is about increasing the impact and
thereby the progress of research itself. A work’s research impact is
an indication of how much it contributes to further research by
other scientists and scholars – how much it is used, applied and
built upon [13–17]. That is also why impact is valued, measured
and rewarded in researcher performance assessement as well as in
research funding [18].
Introduction
The 25,000 peer-reviewed journals and refereed conference
proceedings that exist today publish about 2.5 million articles per
year, across all disciplines, languages and nations. No university or
research institution anywhere, not even the richest, can afford to
subscribe to all or most of the journals that its researchers may
need to use [1]. As a consequence, all articles are currently losing
some portion of their potential research impact (usage and
citations), because they are not accessible online to all their
potential users [2].
This is supported by recent evidence, independently confirmed
by many studies, to the effect that articles whose authors have
supplemented subscription-based access to the publisher’s version
by self-archiving their own final draft to make it accessible free for
all on the web (‘‘Open Access’’, OA) are cited significantly more
than articles in the same journal and year that have not been made
OA. This ‘‘OA Impact Advantage’’ has been found in all fields
analyzed so far – physical, technological, biological and social
sciences, and humanities [3–12]
Self-archiving mandates
Only about 15–20% of the 2.5 million articles published
annually worldwide are being self-archived by their authors today
[8,19]. Creating an Institutional Repository (IR) and encouraging
faculty to self-archive their articles therein is a good first step, but
that is not sufficient to raise the self-archiving rate appreciably
above its current spontaneous self-selective baseline of 15–20%
[20]. Nor are mere requests or recommendations by researchers’
institutions or funders, encouraging them to self-archive, enough
to raise this 20% figure appreciably, even when coupled with offers
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were hence SO/Ø vs. MO/Ø.) The sample covered articles
published between 2002 and 2006. The metadata for the articles
were collected from the four institutional repositories, as well as
from the Thomson-Reuters citation database. (Citation counts
were extracted from the Thomson-Reuters database November,
2008. About two years need to elapse for the citations from the
most recent year to stabilize.)
The effect of OA on citation impact cannot be reliably tested by
comparing OA and non-OA journals because no two journals
have identical subject matter, track-records and quality-standards
(nor are there as yet enough established OA journals in most
fields). The comparison must hence be between OA and non-OA
articles published within the same (non-OA) journals [5]. For each
of the mandated articles, Mi, deposited in our four mandated IRs,
we accordingly collected, as our pool of nonmandated controls for
comparison, the Nj articles that had been published in the same
journal, volume and year. Our sample of self-archived articles
from 2002 to 2006 was distributed across 1,984 non-OA journals
in the Thomson-Reuters database (Table 1). (Based on the
Directory of Open Access Journals (DOAJ), 2% of journals
indexed by Thomson-Reuters in 2006 were OA journals. All
articles from these journals were removed from our pool because
for them O/Ø comparisons were not possible.)
To reduce our nonmandated comparison sample to a
reasonable processing size, we restricted the number of journal/
year-matched controls to the 10 Øj articles that were semantically
closest to their corresponding target Mi (as computed on the basis
of shared words in their titles, omitting stop words). This
tightening of content similarity also made the control articles even
more comparable to their targets than using the full spectrum of
same-journal content. The total size of the article sample (6215
mandated targets plus their 20,982 corresponding controls) from
2002 to 2006 was 27,197. (When more than one M article was
published in the same journal/volume/year (which represents
66% of M articles), only 10 articles were selected as controls, using
keyword matching for one of these M articles.)
The full-text OA status of the articles in our sample was verified
using an automated webwide search-robot [8] as well as an
automated Google Scholar search. (Note that any OA articles that
our robot missed would reduce any OA Advantage. Hence our
estimate of the OA Advantage is conservative.) Figure 1 shows
each of our four mandated institutions’ verified annual OA article
deposits as a percentage of the institution’s total published article
output for each year based (only) on those articles published in the
journals indexed by the Thomson-Reuters citation database; the
resulting estimate of the overall OA mandate compliance rate is
about 60%.(for publishing years 2002–2006, with the deposits up
to 2009, when the analysis was conducted). Note also the robot
data’s confirmation of the approximately 15% baseline for
of help, rewards, incentives and even offers to do the deposit on
the author’s behalf [21]. In two international, multidisciplinary
surveys, 95% of researchers reported that they would self-archive if
(but only if) required to do so by their institutions or funders.
(Eighty-one percent reported that, if it was required, they would
deposit willingly; 14% said they would deposit reluctantly, and only
5% would not comply with the deposit requirement; [22].)
Subsequent studies on actual mandate compliance have gone on
to confirm that researchers do indeed do as they reported they
would do, with mandated IRs generating deposit rates several
times greater than the 20% self-selective baseline and well on the
road toward 100% within about two years of adoption [20].
Universities’ own IRs are the natural locus for the direct deposit
of their own research output: Universities (and research institutions) are the universal providers of all research output, in all
scientific and scholarly disciplines; they accordingly have a direct
interest in hosting, archiving, monitoring, measuring, managing,
evaluating, and showcasing their own research output in their own
IRs, as well as in maximizing its uptake, usage, and impact
[23,24]. OA self-archiving mandates hence add visibility and value
at both the individual and institutional level [25].
In 2002, The University of Southampton’s School of Electronics
& Computer Science (ECS) became the first in the world to adopt
an official self-archiving mandate. Since then, a growing number
of departments, faculties and institutions worldwide (including
Harvard, Stanford, and MIT) as well as research funders
(including all seven UK Research Funding Councils, the US
National Institutes of Health, and the European Research
Council) have likewise adopted OA self-archiving mandates. Over
160 mandates had already been adopted and registered and
charted in the Registry of Open Access Repository Material
Archiving Policies (ROARMAP) as of summer 2010.
In 2008, mindful of the benefits of mandating OA, the council
of the European Universities Association (EUA, consisting of more
than 800 universities, in 46 countries) unanimously recommended
that all European Universities should create IRs and should
require all their research output to be deposited in them
immediately upon publication (to be made OA as soon as possible
thereafter). The EUA further recommended that these selfarchiving mandates be extended to all research results arising
from EU research project funding. A similar recommendation was
made by EURAB (European Research Advisory Board). In the
US, the FRPAA has proposed similar mandates for all research
funded by the major US research funding agencies.
Some studies, however, have suggested that the ‘‘OA Advantage’’ might just be a self-selection bias rather than a causal factor,
with authors selectively tending to make higher-quality (hence
more citable) articles OA [26–29]. The present study was carried
out to test this hypothesis by comparing self-selected OA with
mandated OA on the basis of the research article output of the
four institutions with the longest-standing OA mandates: (i)
Southampton University (School of Electronics & Computer
Science) in the UK (since 2002); (ii) CERN (European Organization for Nuclear Research) in Switzerland (since November,
2003); (iii) Queensland University of Technology in Australia
(since February 2004); (iv) Minho University in Portugal (since
December, 2004).
Table 1. Journal counts per year.
Journal Count
Methods
The objective was to compare citation counts – always within
the same journal/year – for OA (O) and non-OA (Ø) articles,
comparing the O/Ø citation ratios for OA that had been selfselected (S) vs. mandated (M). (The critical comparisons of interest
2002
331
2003
367
2004
415
2005
445
2006
426
TOTAL
1,984
Number of journals in our sample for each year tested.
doi:10.1371/journal.pone.0013636.t001
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Figure 1. Open Access (OA) Self-Archiving Percentages for Institutions With Self-Archiving Mandates Compared to Non-Mandated,
Self-Selected Controls. As estimated from the portion of their yearly published article output that is indexed by Thomson-Reuters, in this 2006
sample at least 60% of each of the four mandated institutions’ total yearly article output was self-archived and hence made OA, as mandated. The
corresponding percentage OA among the control articles published in the same journal/year (but originating from other, presumably nonmandated
institutions) was 15%, or close to the frequently reported global spontaneous baseline rate of about 15–20% for self-selected (nonmandated) selfarchiving [19]. In other words, about 15% of these papers were self-selectively self-archived when it was not mandated, whereas at least 60% were
self-archived when it was mandated.
doi:10.1371/journal.pone.0013636.g001
spontaneous, self-selected (i.e., non-mandated) OA self-archiving
among the control articles in the same journal/years [19].
This mandated deposit rate of 60% is substantially higher than
the self-selected deposit rate of 15–20%. Of course, with anything
short of 100% compliance it remains a logical possibility to hold
onto the hypothesis that the OA citation advantage could be
solely a self-selection bias by arguing that, when self-archiving is
mandated, what used to be a bias toward self-selectively selfarchiving one’s more citable articles instead takes the form of a
selective bias toward noncompliance with the mandate for one’s
less citable articles. But in that case a reasonable expectation
would be at least a substantial reduction in the size of the OA
impact advantage with a mandated self-archiving rate three times
as high as the spontaneous self-archiving rate, were it indeed true
that the OA advantage was solely or largely due to self-selection
bias.
To test whether mandated OA reduces the OA citation
advantage, 4 kinds of articles need to be compared:
–
–
–
–
O
Ø
O
Ø
the logarithms of those ratios for all journals. With OA/OS, there
would be an advantage in favor of OM if the logarithm of the ratio
was greater than zero, and in favor of OS otherwise.
OM=OS~
n
OMj
1X
log
OSj
n j~1
The logarithm is used to normalize the data and to reduce any
effect arising from articles that have relatively high citation counts,
compared to the whole sample. The comparisons are all withinjournal, to minimize between-journal differences in content,
quality and average citation levels (‘‘journal impact factor’’); OA
articles are keyword-matched to their non-OA controls in order to
minimize any differences still further.
Results
Overall, OA articles are cited significantly more than non-OA
articles, confirming the repeatedly observed OA Advantage (O/
Ø). There is also no evidence at all that mandated OA (OM) has a
smaller citation advantage than self-selected OA (OS). Figure 2
shows the results for the four institutions together. Appendix S1
shows each institution separately. The pattern for the individual
institutional data is largely the same as for the average across the
four institutions.
For all OA vs Non-OA (O/Ø) comparisons, regardless of
whether the OA was Self-Selected (S) or Mandated (M), the mean
log citation differences are significantly greater than zero (based on
correlated-sample t-tests for within-journal differences; Table 2).
There is no detectable reduction in the size of the OA Advantage
for Mandated OA (60%) compared to Self-Selected OA (15%).It
would require a very complicated argument indeed (‘‘self-selective
noncompliance for less citable articles’’) to resurrect the hypothesis
that the OA Advantage is only or mostly a self-selection bias in the
face of these findings. (Such an argument does remain a logical
possibility until there is 100% mandate compliance, but an
increasingly implausible one.)
M: OA, Mandated,
M: Non-OA, Mandated,
S: OA, Self-Selected
S: Non-OA, Self-Selected
The analysis uses the citation counts within each journal/year.
Because the date on which the mandate was first adopted varies
(from 2002 to 2004) for the four institutions, we analyzed the data
for the four institutions jointly as well as individually. The
individual analyses show the time-course of mandate compliance
more clearly; the global analysis combines data, enlarges the
sample size and smoothes out incidental effects of institutional and
timing differences.
We compared the following ratios: O/Ø, OM/OS, OS/ØS,
OM/ØM, OM/Ø, OS/Ø and OM/OS using their mean log
citation ratios. For example, to compare mandated OA with selfselected OA, we computed the logarithm of the ratio OMj/OSj for
each journal j and then we computed the arithmetic mean of all
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Figure 2. Log Citation Ratios Comparing the Yearly OA Impact Advantage for Self-Selected vs Mandatory OA 2002–2006. O = OA
article (Open Access); Ø = non-OA article (non-Open Access); M = Mandated OA; S = Self-Selected OA. Averages across the sample of four institutions
with self-archiving mandates confirm the significantly higher citation counts for OA articles (symbolized here as ‘‘O’’) compared to matched control
non-OA articles (symbolized here as ‘‘Ø’’) published in the same journal and year. They are compared as O/Ø log ratios in the seven comparisons. (The
first comparison, O/Ø, for example, is the arithmetic mean of all the (log) ratios O/Ø for each of the 5 years.) OA articles are more highly cited
irrespective of whether the OA is Self-Selected (S) or Mandated (M). The O/Ø Advantage is present for mandated OA (OM/ØS) and is of about the
same magnitude irrespective of whether we compare the S ratios with the M ratios for the entire control sample (OS/Ø vs OM/Ø) or just compare S
alone with M alone (OS/ØS vs OM/ØM). (The larger values for year 2006 are almost certainly due to the fact that 2006 was still too near to have
stabilized at the time this analysis was conducted (2008–9); the analysis has since been extended for years 2006–2008, thereby stabilizing the data for
2006 and 2007, and yields the same results, always with the exception of the most recent year, which was 2008 in the most recent analysis.)
doi:10.1371/journal.pone.0013636.g002
prediction is much better, however, if we use all three predictors
jointly. This is called multiple regression. It gives each of the
predictors a ‘‘weight’’ (ß) that estimates how much it contributes
independently to predicting rain, with the other 2 predictors
factored out. Multiple regression analysis works if the variables are
continuous (like temperature) and normally distributed (i.e., bellcurve-shaped). But if the variables are discrete or not normally
distributed, a variant analysis called logistic regression is used in
which the variables are subdivided above and below a cut-off
point, and various different models, with different cut-off points,
are tested to see which ones predict the target variable the best in
each range. We use this variant analysis, because our variables are
not all continuous or normally distributed. The logistic regression
weights (Exp(ß)) are estimates of the size of the individual
contributions of each of our predictor variables to our target
variable (citations).
(In Table 3 – and in all the other Tables displaying the Exp(ß)
weights for our logistic regressions – the relative size of the Exp(ß)
weight for each of our 15 predictor variables (in each of our
Logistic regression
The number of citations an article receives can be correlated
with and hence influenced by a variety of variables. Those
variables, in turn, could create another kind of bias. For example,
older articles tend to have more citations than younger articles
simply because there has been more time to cite them. If OA
articles tended to be older than non-OA articles, then article age,
rather than OA, could be the cause of the OA Advantage. A way
to test whether correlates of citation other than OA are responsible
for the OA Advantage is to perform a multiple logistic regression
analysis to see whether OA alone is still significantly correlated
with higher citations when the correlation with other variables has
been ‘‘factored out.’’
In ordinary multiple regression analysis, there might be, say,
three ‘‘Predictor’’ variables used to predict a 4th ‘‘Target’’
variable. For example, in weather forecasting, each of (P1)
temperature, (P2) pressure, and (P3) humidity is individually
correlated with, and hence predictive of (T) rain. These three
pairwise correlations are each examples of simple regression. The
Table 2. Paired Samples Test.
Paired Differences
95% Confidence
Interval of the
Difference
Mean
Std. Deviation
Std. Error Mean
Lower
Upper
t
df
Sig. (2-tailed)
Pair 1
O-Ø
1.282
7.402
0.250
0.791
1.772
5.125
875
0.000
Pair 2
OS - Ø
0.890
7.475
0.295
0.312
1.469
3.023
643
0.003
Pair 3
OM - Ø
0.705
6.871
0.286
0.145
1.266
2.470
578
0.014
Pair 4
OS - ØS
0.809
7.535
0.297
0.225
1.393
2.719
641
0.007
Pair 5
OM - ØS
0.647
6.921
0.289
0.080
1.214
2.242
574
0.025
Pair 6
OM - ØM
1.540
9.526
0.684
0.191
2.888
2.251
193
0.026
Pair 7
OM - OS
0.834
7.898
0.421
0.006
1.662
1.982
351
0.048
Significance levels for the 2-tailed t-tests for the 7 differences graphed as log ratios in Figure 2, averaged across 2004–2006 (mandates began to be adopted in 2004).
Open Access (O) vs. Non-Open Access (Ø); Mandated (M) vs. Self-Selected (S). The OA Advantage occurs irrespective of whether the OA is Self-Selected or Mandated.
doi:10.1371/journal.pone.0013636.t002
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Table 3. Set of fourteen variables (plus one interaction) potentially influencing citation counts.
Variable
Description
1
Age
How old is the article (articles published from 2002 to 2006)?
2
JIF
What is the Thomson-Reuters ‘‘Impact Factor’’ (average citations per article in 2-year window) of the journal in which the article was
published (from 0 to 30)?
3
Auth_N
How many co-authors does the article have?
4
Ref_N
How many references does the article cite?
5
Page_N
How many pages in the article?
6
Sci
Is the article classified by Thomson-Reuters as Science (1) or Social Science (0)
7
Review
Is the article classified by Thomson-Reuters as a ‘‘review’’ article (1) or not (0)?
8
USA
What is the country of the first author (USA 1, other 0)?
9
OA
Is the article Open Access (1) or Not (0)?
10
Age*OA
The interaction between Age and OA
11
M
Does the author’s institution Mandate Open Access (1) or Not (0)?
12
CERN
Is the first author from CERN (1/0)?
13
South
Is the first author from Southampton (1/0)?
14
Minho
Is the first author from Minho (1/0)?
15
Queens
Is the first author from Queensland University of Technology (1/0)?
doi:10.1371/journal.pone.0013636.t003
Figure 4 shows that citations are, as is already well-known,
positively correlated with the first eight variables listed earlier
(Age, Journal Impact Factor, Authors, References, Pages,
Science, Review, USA) – as well as with OA. Articles that are
made OA have significantly higher citation counts. In this
analysis the significant OA advantage is independent of the other
variable; it is present in every citation range but highest in the
highest citation range (1–4 citations vs 20+ citations): In other
words, the OA advantage is strongest for highly cited articles.
models, which vary in their ranges and cut-off points) estimates
how much (and in what direction) each predictor contributes to
predicting the target (citations); statistically significant contributions are in boldface. To visualize the size and the direction of the
independent contributions of our predictors, each Table has a
corresponding Figure, showing the contributions as color-coded
bars.)
We have accordingly analyzed the following set of variables that
are potentially influencing citations. Variables 1–8 are known to be
correlated with citation counts. Variable 9 is OA itself; and variable
10 is a measure of the degree to which the relation between OA and
Age is non-additive. Variable 11 indicates whether or not the OA is
mandated. Variables 12–15 are just the four mandating institutions
that are our reference points in this study.
All self-citations were subtracted from the citation counts.
(About 32% of the articles in our sample have at least 1 selfcitation, with an average of about 2 self-citations per article.) As is
well-known, and evident from Figure 3, citation counts are not
normally distributed and instead follow a power-law or stretchedexponential function [19,30,31]. We accordingly used binary
stepwise logistic regression analysis, with a dichotomous dependent
variable, selecting for each test the model that maximizes the chisquare likelihood ratio. To make the interpretation of the
coefficients easier, we exponentiated the ß coefficients (Exp(ß))
and interpreted them as odds-ratios (minus 1, to highlight the
polarity of any change). For example, we can say for the second
model (M2) that for a one unit increase in OA, the odds of
receiving 5–9 citations (versus 1–4 citations) increased by +.323
(i.e., a factor of 1.323). Table 4 and Figure 4 show (Exp(ß)-1)
values for each model with ‘‘x–y cites vs. y–z cites’’ as
dependent variables ((x,y,x) M {1, 2, 3, …, 20}), assigning 1 if the
citation count (minus self-citations) was between y and z and 0 if it
was between x and y. The four models comparing citation ranges
are: (M1) zero vs. lo (1–4); (M2) lo (1–4) vs. med-lo (5–9); (M3) lo
(1–4) vs. med-hi (10–19); (M4) lo (1–4) vs. hi (20+). (The Exp(ß)
values of the variables turned out to have the same polarity and to
be quite similar in magnitude, whether or not self-citations were
substracted.)
Figure 3. Distribution of citation counts (minus self-citations)
for articles. Citation counts are not normally distributed. Of our
sample of 27,197 articles, 23% had zero citations; 51% had 1–5 citations;
12% had 6–10 citations; 8% had 11–20 citations; and 6% had 20+
citations. It is for this reason that a logistic analysis rather than an
ordinary regression analysis was conducted. (Cf. Figure 4, which
presents the distribution of average Journal Impact Factors – which are,
roughly, average citation counts – for journals.)
doi:10.1371/journal.pone.0013636.g003
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Table 4. The (Exp(ß)-1) values for logistic regressions.
Model
M1 (zero/lo)
M2 (lo/med-lo)
M3 (lo/med-hi)
M4 (lo/hi)
Dependent Var.
0 cites
vs
1–4 cites (lo)
1–4 cites (lo) vs
5–9 cites (med-lo)
1–4 cites (lo)
vs
10–19 cites (med-hi)
1–4 cites (lo)
vs
20+ cites (hi)
Age
0.494
0.490
0.786
1.439
JIF
1.229
0.514
0.776
1.114
Auth_N
0.007
0.002
0.002
20.001
Ref_N
0.020
0.016
0.020
0.019
Page_N
20.007
20.014
20.008
Sci
0.249
0.475
0.887
2.050
Review
20.373
20.223
20.008
0.914
0.415
0.406
0.860
0.323
0.392
7.953
0.889
0.716
USA
OA
20.043
Age*OA
0.209
M
CERN
20.032
1.306
20.211
South
Minho
Queens
0.476
14 predictor variables (plus one interaction variable) were used to predict the target variable (citation counts): (1) article age (Age), (2) journal impact factor (JIF), (3)
number of co-authors (Auth_N), (4) number of references cited (Ref_N) , (5) number of pages (Page_N), (6) Science vs. Social Science (Sci), (7) Review article vs. ordinary
article (Review), (8) US co-author vs. no US co-author (USA), (9) open access vs not (OA), (10) non-additive interaction between OA and Age (Age*OA), (11) OA mandated
vs. not (M), (12) mandating institution CERN (CERN), (13) mandating institution Southampton ECS (South), (14) mandating institution U. Minho (Minho), (15) mandating
institution Queensland U. Technology (Queens). Four logistic regression models estimated the size of the independent contribution of each of the 15 predictor variables
to predicting the citation counts using four different cut-off values and comparison ranges (selected on the basis of the overall citation count distribution in Figure 3):
(M1) articles with 0 vs lo (1–4) citations; (M2) lo (1–4) vs. med-lo (5–10) citations; (M3) lo (1–4) vs. med-hi (10–19) citations; (M4) lo (1–4) vs. hi (20+) citations. Note that
OA is a significant independent contributor to citations in all but the lowest of these four citation ranges. The effect is displayed as a bar graph in Figure 5. (Boldface
values for Exp(ß) indicate differences significant at p,0.01 and italic values indicate differences significant at 0.01#p,0.05.)
doi:10.1371/journal.pone.0013636.t004
Figure 4. Exp(ß)-1 values for logistic regressions. These comparisons are based on 4 models, each analyzing a different comparison range. For
each comparison (e.g., 1–4 citations (lo) vs. 5–9 citations (med-lo)) an article is assigned zero if its citation count is in the lower of the two ranges and
one if it is in the upper range. Then the model assigns the best fitting weights to each of the fifteen predictor variables in their joint prediction of the
citation counts. The weights are proportional to the independent contribution of each variable. (Only statistically significant weights are shown.) In
most of the four citation range comparisons (zero/lo, lo/med-lo, low/med-hi, lo/hi), citation counts are positively correlated with Age, Journal Impact
Factor, Number of Authors, Number of References, Number of Pages, Science, Review, USA Author, OA, and Mandatedness. There is also a significant
OA*Age interaction in the top and bottom range. (Citations grow with time; for age-matched articles, the OA Advantage grows even faster with time;
Figure 6). OA is a significant independent contributor in three of the four models and their citation ranges, especially in the the lo/hi comparison.
doi:10.1371/journal.pone.0013636.g004
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(The classification as ‘Review’ is derived from the ThomsonReuters database, which uses number of references cited as its
main criterion for classifying an article as a Review. As the
number of references cited is another one of our predictor
variables, there was probably some confounding of these two
non-independent factors in our analysis. Citations came out as
negatively correlated with the Review variable for the lowmedium citation ranges in our analysis, so it was eliminated in
further analyses.)
In our sample, articles by authors at the mandated institutions
have higher than average citation counts; this effect is present
only in the medium-high citation ranges (and is of course
also influenced by the level of author compliance with the
institutional Mandate, discussed further below). CERN articles
have higher citation counts in the lowest and especially the
highest citation range. However, when all CERN articles are
excluded from our sample, there is no significant change in the
other variables.
There is a significant interaction between Age and OA
(Age*OA) for the lowest citation range comparison, zero/lo (0
vs. 1–4 citations) as well for the highest comparison, lo/hi (1–4
citations vs. 20 citations and more). Both the linear main effect
of age and OA, and this nonlinear interaction are statistically
significant. Figure 5 illustrates the Age*OA interaction effect
for the lo/hi range comparison using the means for OA and
Non-OA citation counts for each article age. The pattern again
confirms the OA advantage but also shows that in the lo/hi
comparison range the advantage increases more for older
articles, over and above what would be expected from age
alone.
the articles:
JIF1
JIF2
JIF3
JIF4
:
:
:
:
0ƒJIFv0:63
0:63ƒJIFv1:05
1:05ƒJIFv1:78
1:78ƒJIFv29:96
Only the top quartile contains journals with JIFs from 1.78 to
29.96. As we are also interested in the variability within this top
quartile, we further subdivided it into two octiles, each covering
12.5% of the articles. (Subdividing more minutely would make the
sample sizes too small to detect effects of interest.) This yielded a
total of five ranges for the JIF variable:
JIF1 : 0ƒJIFv0:63
JIF2 : 0:63ƒJIFv1:05
JIF3 : 1:05ƒJIFv1:78
JIF4 : 1:78ƒJIFv2:47
JIF5 : 2:47ƒJIFƒ29:96
The same regression is done separately for each JIF range by
controlling all the variables (except JIF). Figures 7, 8, 9, 10, 11
(and Appendix S2: Table S2a–S2e) summarize the values of
Exp(ß)-1 corresponding to the controlled variables for each JIF
range. (As noted earlier, our Exp(ß) values for these variables
exhibit the same polarity and pattern whether or not we exclude
self-citations from the citation count.)
When articles are published in a low JIF journal, citation counts
for their individual articles are positively correlated with Age,
References, Authors, OA and M. The OA advantage is greater in
the higher citation ranges. For the lowest range of individual
article citations, the Age*OA interaction is significant, but OA
itself is not.
For articles in journals with JIFs between 0.63 and 1.05, the
pattern is quite similar, except that the Age*OA interaction is
absent and OA itself (alongside Age, as separate variables) is
significant.
For articles in journals with JIFs between 1.05 and 1.78, the
pattern is again quite similar. The USA and Review variables now
also correlate with citation increase.
For journals with JIFs between 1.78 and 2.47, longer articles
(more pages) have more citations. Here the OA advantage is
significant only in the highest citation count ranges. The number
of authors is also less correlated with increased citations as the
citation range gets higher. CERN and QUT have a citation
advantage in this JIF range. However, removing the articles from
these institutions does not alter the pattern for the other variables.
For journals with JIFs between 2.47 and 29.96. The OA
advantage is again significant for the highest citation ranges. (The
increased citations for USA and Review articles also increase in
significance). In this JIF range, CERN has a citation advantage in
medium-high citations ranges. Removing the articles from this
institution, however, does not change the pattern for the other
variables.
Overall, OA is correlated with a significant citation advantage
for all journal JIF intervals as well as for the sample as a whole.
This advantage is greatest for the highest citation ranges. When
regressions are done separately for the different JIF ranges, the
Age*OA interaction disappears, but OA and Age (as separate
variables) remain significant. (There is no significant effect of a
specific institution compared to the rest of the institutions, hence
Logistic regression by Impact Factor interval
In order to compare articles published in comparable journals
and to see the profile for journals in increasing impact ranges (see
distribution, Figure 6), we divided our sample into 4 quartiles in
terms of Journal Impact Factor (JIF), each range covering 25% of
Figure 5. Interaction between OA and article age. Over and
above the sum of the independent positive effects on citations of OA
alone and of age alone, the size of this OA Advantage increases as
articles get older. The interaction is illustrated here for the lo/hi (1–4/
20+) citation range comparison (model M4) for articles that were from 3
years old (2006) to 7 years old (2002). (The comparison was made in
2009.)
doi:10.1371/journal.pone.0013636.g005
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Figure 6. Distribution of Journal Impact Factors by Journal. As with the distribution of individual article citation counts (Figure 3), the
distribution of journal impact factors (average citation counts) is highly skewed. Most journal JIFs fall between 0 and 5, with the peak between 2 and
3, followed by a long rapidly shrinking tail, tail with very few journals having a JIF greater than 10.
doi:10.1371/journal.pone.0013636.g006
significantly with an independent positive increase in citation
counts even when the contributions of all these other correlates are
calculated independently means that the OA Advantage is not just
a bias arising from either a random or a systematic imbalance in
the other correlates of citations.
Moreover, the OA advantage is just as great when the OA is
mandated (with mandate compliance rate ,60%) as when it is
self-selective (self-selection rate ,15%). This makes it highly
unlikely that the OA advantage is either entirely or mostly the
result of an author bias toward selectively self-archiving higher
quality – hence higher citability – articles. Nor are the main effects
the result of institutional citation advantages, as the institutions
there is no need to exclude any specific institution from our
sample.)
Discussion
This study confirms that the OA advantage is a statistically
significant, independent positive increase in citations, even when
we control the independent contributions of many other salient
variables (article age, journal impact factor, number of authors,
number of pages, number of references cited, Review, Science,
USA author). All these other variables are of course correlated
with citation counts, so the fact that OA continues to correlate
Figure 7. Exp(ß)-1 values for logistic regressions (Lowest JIF Range: 0.0–.0.63). (See Figure 5 for explanation of analysis and
interpretation.) In this lowest range of journal impact factors, the biggest factor contributing to citation in all citation range comparisons is article age.
OA is an important contributor in the two upper range comparisons.
doi:10.1371/journal.pone.0013636.g007
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Figure 8. Exp(ß)-1 values for logistic regressions (JIF range 0.63–1.05). (See Figure 5 for explanation of analysis and interpretation.) In the
second lowest JIF range, article age continues to be the main factor in all four citation ranges, with OA emerging and growing in the top three.
doi:10.1371/journal.pone.0013636.g008
were among the independent predictor variables in the logistic
regression; the outcome pattern and significance is also unaltered
by removing CERN, the only one of the four institutions that
might conceivably have biased the outcome because its papers
were all in one field and tended to be of higher quality, hence
higher citability overall.
Since, with the exception of our one unidisciplinary institute –
CERN (high energy physics) – the pluridisciplinary articles from
the three other mandated institutional repositories are mostly not
in fields that habitually self-archive their unrefereed preprints well
before publication (as many in high energy physics do), nor in
fields that already have effective OA for their published postprints
(as astronomy does: [9,28,32]), it is also unlikely that the OA
advantage is either entirely or mostly just an early-access
(prepublication) advantage [33,34]. This will eventually be testable
once there are enough reliable data available on deposit-date,
relative to publication-date, for a large enough body of selfarchived OA articles. In any case, an early-access advantage in a
preprint self-archiving field translates into a generic postpublication OA advantage in that vast majority of fields in which authors
do not self-archive their prepublication preprints and so their
published postprints are accessible only to subscribers – except if
they have also been self-archived. The OA mandates all apply only
to refereed postprints, self-archived upon publication, not to prerefereeing preprints, self-archived before publication.
This study confirms that the OA advantage is substantially
greater for articles that have successfully met the quality standards
of higher-impact journals and it is also greater in the highercitation ranges for individual papers within each journal-impact
level. The typical Pareto distribution for citations whereby the top
10–20% of articles receive about 80–90% of all citations [35], is
present in our own sample of 708,219 articles extracted from
Thomson-Reuters from 1998 to 2007: about 20% of articles
received about 80% of all citations. In addition, 10% of journals
receive 90% of all citations.
The implication is that OA itself will not make an unusable
(hence uncitable) paper more used and cited (although the
proportion of uncited papers has been diminishing with time;
[31]). But wherever there are subscription-based constraints on
accessibility, providing OA will increase the usage and citation of
the more usable and citable papers, probably in proportion to their
importance and quality, hence citability. We accordingly infer
from our results that the most likely cause of the OA citation
advantage is not author self-selection toward making more citable
articles OA, but user self-selection toward using and citing the more
citable articles – once OA self-archiving has made them accessible
Figure 9. Exp(ß)-1 values for logistic regressions (JIF range 1.05–1.78). (See Figure 5 for explanation of analysis and interpretation.) In this
middle range of journal JIFs, article age continues to be influential, and OA is a significant factor in three of the four citation ranges.
doi:10.1371/journal.pone.0013636.g009
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Figure 10. Exp(ß)-1 values for logistic regressions (JIF range 1.78–2.47). (See Figure 5 for explanation of analysis and interpretation.) In this
next-to-highest JIF range, OA has its effect only in the top range (lo/hi).
doi:10.1371/journal.pone.0013636.g010
selective basis today than among the 20% that are; the result is
that the OA mandates serve to help bring this ‘‘cream of science’’
to the top.
It also needs to be noted that some of the factors contributing to
the OA advantage are permanent, whereas others will shrink as
OA rises from its current 15–20% level and will disappear
completely at 100% OA. All competitive advantage of OA over nonOA (because OA is more accessible) will of course vanish at 100%
OA (as will the possibility of concurrent measurement of the OA
Advantage). Any self-selective bias (whether positive or negative) will
likewise disappear at 100% OA. What will remain will be the
quality advantage itself (the tendency of researchers to selectively use
and cite the best research, if they can access it), but maximized by
leveling the playing field, making everything accessible to every
user online.
There will continue to be the early-access advantage in fast
turnaround fields: It is not that making findings accessible earlier
to all users, rather than just to those whose institutions could afford
subscription access. In other words, we conclude that the OA
advantage is a quality advantage, rather than a quality bias: it is not
that the higher quality articles – the ones that are more likely to be
selectively cited anyway – are more likely to be made OA selfselectively by their authors, but that the higher quality articles that
are more likely to be selectively cited are made more accessible,
hence more citable, by being made OA.
Our results also suggest the possibility that mandated OA might
have some further independent citation advantage of its own, over
self-selected OA – but until and unless this effect is replicated, it is
more likely that this small, previously unreported effect was due to
chance or sampling error. If there does indeed prove to be an
independent ‘‘mandate advantage’’ over and above OA itself, a
possible interpretation would be the reverse of the self-selection
hypothesis: There may be a higher proportion of higher-quality
work among the 80% that are not being made OA on a self-
Figure 11. Exp(ß)-1 values for logistic regressions (JIF 2.47–29.96). (See Figure 5 for explanation of analysis and interpretation.) In this, the
highest JIF range, article age again increases citations in all ranges, whereas OA again has its effect only in the top range (lo/hi) (Note the anomalous
effect of the ‘‘Review’’ variable; this is probably because it is confounded with the Reference count variable; when Review was removed in further
analyses, the pattern of the other variables, and in particular OA, was unchanged.)
doi:10.1371/journal.pone.0013636.g011
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merely gets them their citation ‘‘quota’’ earlier; providing OA
earlier significantly increases that quota, probably by both
accelerating and broadening the uptake of the findings in further
research [33]. And even after the competitive advantage is gone
because all articles are OA, the download advantage will continue to
be enjoyed by all articles [36,37] (thereby potentially influencing
research even where it does not generate citations), while the
quality advantage will see to it that for the best work, increased
downloads are translated into uptake, usage and eventual
increased citations. (Higher download counts earlier on have been
found to be correlated with, hence predictive of, increased citation
counts later; [38].)
achieve its full impact potential, no longer constrained by today’s
needless limits on its accessibility to its intended users [39–42].
To measure that maximized research impact, we and others are
already developing new OA metrics for monitoring, analyzing,
evaluating, crediting and rewarding research productivity and
progress [18,36,38,43–52]. Hence there is no need to have any
penalties or sanctions for non-compliance with OA self-archiving
mandates. As the experience of Southampton ECS, Minho, QUT
and CERN has already demonstrated, OA mandates, together with
OA’s own intrinsic rewards (enhanced research access, usage and
impact), will be enough to reinforce the causal connection between
providing access and reaping its impact, through the research
community’s existing system for evaluating and rewarding research
productivity. In the online era, researchers’ own ‘‘mandate’’ will no
longer just be ‘‘publish-or-perish’’ but ‘‘self-archive to flourish.’’
Summary and Conclusion
The assumption that increasing access to research will increase
its usage and impact is the main rationale for the worldwide OA
movement. Many prior studies have by now shown across all fields
that journal articles that are made freely accessible to all potential
users are cited significantly more than articles that are accessible
only to subscribers. There is prior evidence for a self-selection bias
toward the preferential self-archiving of higher quality articles in a
few special fields (such as astronomy and some areas of physics)
where most articles are made OA in unrefereed preprint form long
before they are refereed and published, and where the published
version is effectively accessible to all potential users as soon as it is
published. Authors may indeed be more reluctant to make the
preprints of papers about which they have doubts freely accessible
online before they are refereed [29,33]. But we have now shown
that for most other fields (i) the OA Advantage remains just as high
for mandatory self-archiving as for self-selected self-archiving and
that (ii) this is not an artifact of systematic biases in other correlates
of citation counts. Both the self-archiving and the mandates apply
to refereed postprints, upon acceptance for publication, not to
unrefereed preprints.
Hence the OA Advantage is real, independent and causal. It is
indeed true that the size of the advantage is correlated with quality,
just as citations themselves are correlated with quality (the top 20%
of articles receiving about 80% of all citations); but we infer that the
real cause of the higher OA advantage for the more citable articles is
not a quality bias from author self-selection but the quality
advantage of the more citable articles, an advantage that OA
enhances by maximizing accessibility, and thereby also citability. On
a playing field leveled by OA, users can selectively access, use and
cite those articles that they judge to be of the highest relevance and
quality, no longer constrained by their accessibility.
Overall, only about 15–20% of articles are being spontaneously
self-archived today, self-selectively. To reach 100% OA globally,
researchers’ institutions and funders need to mandate self-archiving,
as they are now increasingly beginning to do. We hope that this
demonstration that the OA Impact Advantage is real and causal will
provide further incentive and impetus for the adoption of OA
mandates worldwide in order to ensure that research can at last
Supporting Information
Appendix S1 OA Impact Advantage for each Institution.
Figure 2 showed the mean log citation ratios for O/Ø, OM/
OS, OS/ØS, OM/ØM, OM/Ø, OS/Ø and OM/OS for the
four institutions together. The outcome was that the Open Access
(OA) citation advantage was present and roughly equal whether
the OA was Self-Selective (S) or Mandated (M). That showed that
the OA Advantage is not merely an artifact of author self-selection.
This appendix shows the results for each institution separately. As
will be evident, the pattern for the individual institutional data is
largely the same as it is for the average across the four institutions.
Found at: doi:10.1371/journal.pone.0013636.s001 (0.21 MB
DOC)
Appendix S2 Multiple regression by JIF - Beta values. The
multiple logistic regression we applied to our total sample of
journals is applied here separately to the journals in each JIF
(Journal Impact Factor) range by including all the other 14
predictor variables, apart from JIF itself. Tables S2a–S2e
summarize the values of Exp(b)-1 corresponding to the predictor
variables for each JIF range. The results were discussed in
Figures 7–11. In sum, they show that whereas citation counts grow
with an article’s age across all the citation range comparisons for
our four models (zero/low, low/medium1, low/medium2, low/
high), OA’s contribution tends to be more on the high-citation
end, being greater in the higher JIF range (JIF4–JIF5) among
journals and in the low/high range comparisons (M4) among
articles.
Found at: doi:10.1371/journal.pone.0013636.s002 (0.13 MB
DOC)
Author Contributions
Conceived and designed the experiments: LC SH. Performed the
experiments: YG CH. Analyzed the data: YG CH TB. Contributed
reagents/materials/analysis tools: VL YG LC TB. Wrote the paper: SH.
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Universitetet for miljø- og biovitskap
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October 2010 | Volume 5 | Issue 10 | e13636
Møtedato 09.11.2010