Work Description

Citations to Open and Closed Access Articles: Treatment and Control Group Data

This random sample of OA articles comes from Deep Blue , the University of Michigan’s institutional repository service. Each OA article has the following characteristics: Prior to a known date (ranging from 2006 to the 2013) these articles—the final published version—were only available by subscription. After that date, they became freely available via Deep Blue. Meanwhile, other articles from the same journal issue as the now-OA article continued to only be available to subscribers. None of the OA articles were self-selected; authors did not choose to deposit the articles in question in Deep Blue, since we made them open via blanket licensing agreements between the publishers and the library.

The sample is a random selection of 3,850 papers—peer-reviewed and review articles only; bibliographies, book reviews, corrections, discussions, editorials, letters, notes, etc. were not considered—with original publication dates ranging from 1990 to 2013. These are matched with the 89,895 corresponding articles which remained closed, using the specific journal issue as a proxy for comparability of subject matter and quality.

Using data from Thomson Reuters’ Web of Science and Journal Citation Reports databases, we get actual citations before and after OA for all articles.

Some metadata elements were anonymized to preserve the privacy of the authors, and others were anonymized or removed at the request of Thomson Reuters.

The following sheets are included in "Citation_Study-Master_Data_SetANONYMIZED-1990-2013":

UM only: citation data for UM-authored articles which were opened, along with aggregated citation data for the other articles (which remained closed) from the same journal issue in which they appeared.

UM+99% close equivalents: a subset of 'UM only', including only those articles where the citations to an opened article and its closed equivalent(s) differ by <1% during the period when both were closed

non-UM (always closed): all the articles used to compare against the opened (UM only) articles.

non-UM (>median only, always cl[osed_)]: all the closed/non-UM articles corresponding to the better-than-median (while closed) UM articles.

The following sheets are included in "Citation_Study-Master-Data_SetANONYMIZED-2006-2013:

UM only: citation data for UM-authored articles with a first publication date of 2006-2013 which were opened, along with aggregated citation data for corresponding articles from the same journal/issue in which they appeared.

UM only, open >85% of time: a subset of 'UM only' from "Citation_Study-Master_Data_SetANONYMIZED-1990-2013", including only those articles where the UM-authored articles were open more than 85% of the time since their first publication

non-UM (always closed): all the articles used to compare against the opened (UM only) articles.

These sheets include the following fields:

date opened: date an article was made OA, removing the exact time of day (for anonymization purposes)

indexing: "MetadataOnlyIndexed": only the article's descriptive metadata (title, author, etc.) was indexed by e.g. Google; "FullTextIndexed": both descriptive metadata and the full text of the article were indexed by e.g. Google

anonymized title: title of the article, anonymized

anonymized journal name: journal name, anonymized (while preserving discipline information)

document type: "Article" or "**Review**" (i.e., a review article)

volume/issue: volume/issue information anonymized to create a unique value when combined with 'anonymized journal name' and 'anonymized title'

publication year: year article was published

impact factor: Thomson Reuter's Impact Factor for the journal the article(s) appeared in

≤2006 Cites: citations to the article through 2006
2007 Cites: citations to the article in 2007
2008 Cites: citations to the article in 2008
2009 Cites: citations to the article in 2009
2010 Cites: citations to the article in 2010
2011 Cites: citations to the article in 2011
2012 Cites: citations to the article in 2012
2013 Cites: citations to the article in 2013
2014 Cites: citations to the article in 2014

UM closed: citations to an opened (UM-authored) article while it was closed

UM open: citations to an opened (UM-authored) article once it was opened (made OA)

other closed: mean citations for the corresponding other articles in the journal/issue during the period when the UM article was closed

other open: mean citations for the corresponding other articles in the journal/issue during the period once the UM article was made OA

median closed: median citations for the corresponding other articles in the journal/issue during the period when the UM article was closed

median open: median citations for the corresponding other articles in the journal/issue during the period once the UM article was made OA

equivalent closed: mean citations for the nearest equivalent article in the journal/issue during the period when the UM article was closed

equivalent open: citations for the nearest equivalent article in the journal/issue during the period when the UM article was made OA

mean expected value: expected number of citations for the UM-authored (opened) article if its citation pattern pre- and post-OA matched the mean article in that journal issue

median expected value: expected number of citations for the UM-authored (opened) article if its citation pattern pre- and post-OA matched the median article in that journal issue

equivalent expected value: expected number of citations for the UM-authored (opened) article if its citation pattern pre- and post-OA matched the nearest equivalent article(s) in that journal issue

actual-mean expected: 'UM open' - 'mean expected value'

actual-median expected: 'UM open' - 'median expected value'

actual-equivalent expected: 'UM open' - 'equivalent expected value'

years available: amount of time since publication a UM article was available (month information not available for the journal issue)

years open: amount of time since publication a UM article was open (calculated using the month+day information available from Deep Blue)

% time open: 'years open'/'years available'

Cells highlighted in yellow are those that contain values for the nearest equivalent article in the journal/issue during the period when the UM article was closed.

Cells where the numeric value is red are colored as a visual reminder that these are the years during which the article was closed.