What is the impact of open access journals relative to ‘closed’ ones? | Caitlin Rivers

Use the link to access the graphs described in the following blog post: "After I wrote about the apparent decline in interest in open source/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 (SGR).  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.'  Alternatively, SJR ‘is a measure of the scientific prestige of scholarly sources. SJR assigns relative scores to all of the sources in a citation network. Its methodology is inspired by the Google PageRank algorithm, in that not all citations are equal. A source transfers its own ‘prestige’, or status, to another source through the act of citing it. A citation from a source with a relatively high SJR is worth more than a citation from a source with a lower SJR.'

All analysis were done in an ipython notebook, and relied heavily on pandas. You can view the notebook here, and regular .py code here..."