Comments on: Does a Citation Advantage Exist for Mandated Open Access Articles?

By: Is There an Open-Access Citation Advantage? » iThinkEducation.net!

Is There an Open-Access Citation Advantage? » iThinkEducation.net! — Tue, 26 Oct 2010 23:58:07 +0000

[...] reliable is that conclusion? When a preprint of the article circulated earlier this year, there was a lively debate about its merits on the Scholarly Kitchen blog. Philip M. Davis, a postdoctoral associate in the [...]

By: Is There an Open-Access Citation Advantage? - Wired Campus - The Chronicle of Higher Education

Tue, 19 Oct 2010 20:38:04 +0000

By: Repositories in the Cloud? Why on earth not?! | CloudAve

Repositories in the Cloud? Why on earth not?! | CloudAve — Tue, 23 Feb 2010 17:44:10 +0000

[...] Does a Citation Advantage Exist for Mandated Open Access Articles? (scholarlykitchen.sspnet.org) [...]

By: Repositories in the Cloud? Why on earth not?! | Paul Miller - The Cloud of Data

Sun, 21 Feb 2010 18:05:55 +0000

[...] Does a Citation Advantage Exist for Mandated Open Access Articles? (scholarlykitchen.sspnet.org) [...]

By: Yassine Gargouri

Yassine Gargouri — Tue, 09 Feb 2010 16:07:03 +0000

Your confusion is our fault. The problem is with our having used the value 0.957 by way of an illustration. We should have chosen a better example, where (Exp(ß)) is clearly greater than 1; the value 0.957 is too close to 1, but below 1, to serve as an illustration. We should have said: “For the second model, a one-unit increase in OA, the odds of receiving 5-10 citations (versus zero 1-5 citations) increased by a factor of 1.323.” (This clearer example will be used in the revised text of the paper.)

By: Stevan Harnad

Stevan Harnad — Mon, 08 Feb 2010 18:57:34 +0000

(a) The logistic regressions in Figures 4 and 7-11 test whether the four mandated institutions make a significant independent contribution to the citation counts in 5 journal impact-factor ranges and 4 citation quartiles for each. Most of the OA citation advantage is concentrated in the top of the four citation ranges in each figure. Of the 4 mandated institutions, Minho and QUT never have an independent citation advantage in those top citation ranges; CERN does twice (top range of Figuress 4 & 10), but removing CERN does not alter the pattern; and Southampton does once (top range of Figure 9), but removing Southampton too does not alter the results. The OA advantage is present and strong in all 5 of the top ranges.

See: SUPPLEMENTARY FIGURE S1:
http://eprints.ecs.soton.ac.uk/18346/7/Supp1_CERN%2DSOTON.pdf

(b) Each of the separate paired-sample t-tests for each of the four mandated institutions individually (Figures 12-16) likewise shows the same overall pattern: a citation advantage of the same size as for self-selected OA (as in Figure 2, which shows the joint effect for all four mandated institutions).

(c) If U. Leiden had been in our sample, it would have been computed as an unmandated institution. Its OA articles would have shown the usual OA advantage. In addition, if Leiden is indeed an above-average university, it would have shown an independent citation advantage, as CERN did, especially in the high journal impact-factor ranges and citation quartiles.

By: Sur le front du libre (17/01/10) « pintiniblog

Sur le front du libre (17/01/10) « pintiniblog — Sun, 17 Jan 2010 09:43:59 +0000

[...] Does a Citation Advantage Exist for Mandated Open Access Articles? (source: The Scholarly Kitchen, 07/01/2010 / l’avis des éditeurs sur l’article [...]

By: Ludo Waltman

Ludo Waltman — Mon, 11 Jan 2010 16:09:09 +0000

I am still worried about the effect of institutional differences on the analysis. The authors have indeed performed a separate analysis in which CERN is left out, but this doesn’t solve the problem. The three other institutes may also produce papers whose quality is on average above the quality level of similar papers (published in the same journal), and this may explain any differences in citation counts. Hence, differences in citation counts may be due to at least two reasons: (1) quality differences among institutes and (2) the presence or absence of a mandatory open access policy. Using the current design, it is not possible to distinguish between these two possibilities.

Suppose that we take my own institute, Leiden university, and that for each paper from my institute we find 10 similar papers from other institutes (published in the same journal). Suppose next that we compare the citation counts of the two sets of papers. My guess is that the papers from my institute will on average receive more citations than the papers from the other institutes. However, there is no mandatory open access policy at my institute. So where do these above average citations come from? A possible explanation is that these citations are due to quality differences between my institute and other institutes doing similar research. This possibility is ignored in the analysis of Gargouri et al.

By: Philip Davis

Philip Davis — Sun, 10 Jan 2010 01:15:16 +0000

Thank you Yassine.

This change in how you calculate your ratios makes a VERY BIG difference to your paper.

Still, any ratio that has zero in the denominator is necessarily tossed from your dataset.

How much of your data did you have to toss for these calculations? And would tossing these ratios lead to any systematic bias in your dataset?

Would adding +1 to every citation count before transformation change your results (this is a common technique used with there are zeros in a dataset)?

Lastly, have you attempted to perform a regression analysis that treats your citation data as a variable (e.g. 0,1,2,3…) rather than categorical data (e.g. 0, 1-5, 10-20, 20+)?

By: Philip Davis

Philip Davis — Sun, 10 Jan 2010 01:05:34 +0000

Thanks Yassine,
I’ve re-read page 9 and I’m still not sure what Cit_a_0&1-5 means, but an Odds Ratio that is below 1.0 means a DECREASE in odds, not an increase.