Historians, economists, biochemists, psychologists: Who reuses their own material most often? Does the rate depend on how many authors a paper has, and how far along a researcher is in his or her career? Serge Horbach and Willem Halffman at Radboud University Nijmegen in the Netherlands tried to answer these questions by reviewing more than 900 papers published by researchers based in The Netherlands. And they were surprised by their findings, published last month by Research Policy.

Retraction Watch: How does the amount of text recycling you identified among researchers at Dutch universities (6.1%) compare to what other studies have shown among other groups of researchers?

Willem Halffman and Serge Horbach: Previous studies found varying degrees of text recycling, ranging from 3% to as much as 60%. Ours is, as far as we know, the biggest study on text recycling so far (N=922). Hence we think our figure of 6% is more realistic. However, the precise degree of text recycling depends very much on the threshold used. We used 10% of the text as our detection limit and then stuck to the Dutch guidelines for acceptable text recycling in our manual check. Judging the acceptability of text reuse depends on conventions that may be implicit, or vary between publication cultures of different research fields or even countries. Hence, we think our main finding is not so much the number of 6%, but the variation behind that number. We had expected to find more recycled text in biochemistry, where you could expect formulaic descriptions of highly standardised methods, but there was hardly any. Among Dutch historians we found virtually no text recycling. However, among Dutch psychologists text recycling is more elevated and among economists it is as much as one in seven publications. Text recycling also occurs more often among productive authors, in papers with fewer co-authors, and in journals that do not specify clear rules. This variation is more informative about the origins of text recycling than the overall degree.

Read the rest of this interview

Also see

Horbach SPJM (Serge) , Halffman W (2017) The extent and causes of academic text recycling or ‘self-plagiarism’. Research Policy. ISSN 0048-7333, https://doi.org/10.1016/j.respol.2017.09.004.
Publisher (open access): http://www.sciencedirect.com/science/article/…