All That Matters

As this week there is again a lot of talk about journal impact factors with the release of this year’s data later today, I like to take this timely opportunity to look at citation metrics more broadly, in terms of fundamental flaws in weighing data, and important data missing in the underlying data sets, which in my view miss important data when it comes to practical, technological impact of a study.

I recently had the opportunity of attending a talk by Paul Wouters from Leiden University, a professor of scientometrics. He pointed out one of the fundamental flaws in citation metrics that goes right to the heart of such data collection, before one should even discuss more superficial metrics such as h-index or the impact factor. Like any other piece of data, the context of a citation matters, he said. Factors that play a role are the type of paper where a reference is cited, and in what way. Was it criticism? Controversial papers for a while at least can gather a lot of citations even though eventually their impact on scientific process can be nil. There are also human aspects. Relevant points here are who cited a paper, was it a self-citation, or were there other motivations for citations? After all, citation cartels are not unheard of.

There is a lot of literature on various aspects of citation analysis, and more details on this can be found in Wouters’ doctoral thesis on citation culture, or in the 2008 paper by Jeppe Nicolaisen on citation analysis.

More broadly speaking, I am not sure whether it will be possible to properly analyse and process context when it comes to citation analysis. There are too many ways to game such systems. However, a more complex analysis might well be possible, taking the example of he ranking of web sites in search engines. There, context is everything. A website that is linked from many other sites is not necessarily an important one. Instead, a link to a web site from an important web outlet such as a popular news web site weighs much more than links from unknown web sites. Indeed, many links from news web sites or social networks might also be an indicator of immediacy, further propelling a site up the search engine rankings. […]