LAUSR

In a recent study (Mansourzadeh, Shahmoradi, Dehdaridad and Janavi 2019) the authors study the Balassa or revealed competitive advantage (RCA) index (Balassa 1965) and apply its algorithm to research evaluation studies. They further point out some problems when applying this index in a bibliometric context. Unfortunately, this article misses a large part of the applications of this algorithm. It seems that the authors are unaware of the fact that the Balassa algorithm is the same as the algorithm used in the calculation of the activity index (dealing with publications) and denoted as AI, and is essentially the same as the algorithm used for the Relative Specialization Index (RSI). Indeed, the relative specialization index (RSI) as used e.g., in Glänzel (2000) is defined as:RSI = AI−1