Tests and confidence intervals for a class of scientometric, technological and economic specialisation ratios

In economic, scientometric, and innovation research, often so-called specialisation indices are used. These indices measure comparative strengths or weaknesses as well as specialisation profiles of the observation units with respect to certain criteria, such as patenting and publication or trade activities. They allow question like: Is Germany specialised in the export of motor vehicles? Or is the UK specialised in biotech patents? Unfortunately, little is known about their statistical properties, which makes valid inferencing difficult. In this article we prove asymptotic normality for a certain class of scientometric, technological, and some economic, though non-monetary, specialisation indices. We provide asymptotic confidence intervals and demonstrate in an example how to obtain statistically sound results. We will also address the problem of normalisation of these indicators. All procedures proposed are provided in an add-on package for R statistical environment.