This post was originally written on 1/26/2013, and updates on 3/18/2013
After I wrote about the apparent decline in interest in open access/science, one commenter suggested that search volume may be declining as the concepts become more mainstream. Here are those trends again, without open science to obscure the lower search volume terms.
It’s a classic research conundrum - is the effect we are observing real?
I looked into it more using data specifically on open access and open science. I downloaded a list of open access journals from the Directory of Open Access Journals (DOAJ). I also downloaded a spreadsheet of 2011 impact data from Journal Metrics, an offshoot of Scopus that assesses journal impact. Journal Metrics provides two impact measures: Source Normalized Impact per Paper (SNIP) and SCImago Journal Rank (SJR). I will mostly be using SNIP score for this analysis.
According to their FAQ, SNIP “measures a source’s contextual citation impact. It takes into account characteristics of the source's subject field, especially the frequency at which authors cite other papers in their reference lists, the speed at which citation impact matures, and the extent to which the database used in the assessment covers the field’s literature. SNIP is the ratio of a source's average citation count per paper, and the ‘citation potential’ of its subject field. It aims to allow direct comparison of sources in different subject fields.”
All analysis were done in an ipython notebook, and relied heavily on pandas. You can view the notebook here, and regular .py code here. You can also download figures or obtain a doi at figshare.
There are quite a few more analysis available on the ipython notebook (no coding skills necessary, its a webpage). Here is the link again.
There are more journals published in the United States than any other country. Nevertheless, the US lags behind on open access. In fact, the US is not even in the top 50 - just 13% of journals in the US are OA. Colombia, Costa Rica, and Egypt lead the pack, with an open:closed ratio of 35, 26, and 17, respectively.
In terms of impact, open access still lags behind non-OA journals. A longer-term perspective yields mixed results. Although the median SNIP value has risen from .34 in 1999 to ,47 in 2011 for OA journals, non-OA journals has seen a similar increase, which suggests that journals regardless of access type are reaching more people**.
On the bright side, there is some evidence the gap may be closing. The median SNIP difference fell from .35 in 1999 to .20 in 2011.
Because the academic journal publishing industry is dominated by four countries (US, UK, Netherlands, and Germany), I separated the scores by country of origin. In Big 4 countries, there is an overall trend of increasing impact for both open and closed journals, with a huge gain for open access journals in particular. In non Big 4 countries, open access journals continue to yield a higher impact score than their non-OA counterparts.
Within individual countries, the relative impact of open access and non-open access journals varies widely. For some, open journals have an even higher impact than closed journals. Journals published Brazil, Belgium, India and Japan have the highest median SNIP scores.
Unfortunately, journals published in the Netherlands, UAE, New Zealand, and the United States tend to favor closed-access journals. Open access journals have lower impact scores in those countries relative to closed access journals.
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