Ratings and rankings: Voodoo or Science?

Composite indicators aggregate a set of variables using weights which are understood to reflect the variables' importance in the index. In this paper we propose to measure the importance of a given variable within existing composite indicators via Karl Pearson's `correlation ratio'; we call this measure `main effect'. Because socio-economic variables are heteroskedastic and correlated, (relative) nominal weights are hardly ever found to match (relative) main effects; we propose to summarize their discrepancy with a divergence measure. We further discuss to what extent the mapping from nominal weights to main effects can be inverted. This analysis is applied to five composite indicators, including the Human Development Index and two popular league tables of university performance. It is found that in many cases the declared importance of single indicators and their main effect are very different, and that the data correlation structure often prevents developers from obtaining the stated importance, even when modifying the nominal weights in the set of nonnegative numbers with unit sum.Comment: 28 pages, 7 figure

International higher education and the mobility of UK students

In the context of increasing academic interest in the internationalization of education and the international mobility of university students, this article draws on findings of a recent research project examining students from the UK as they seek higher education overseas before entering the labour market. The discussion is framed around four key themes (the importance of `second chances'; `global circuits of higher education'; `experiences of travel' and `labour market outcomes'), which address the motivations and experiences of 85 individuals who are seriously considering or have recently obtained an international degree