[On the importance of nonparametric approaches for a comparison of income inequality in different countries]

"A comparison of income inequality in different countries can be made on the basis of parametric or nonparametric approaches. Using nonparametric instead of parametric approaches may raise the validity of such comparisons in some respects. However, new sources of validity reduction may be linked with nonparametric approaches. An important source of validity reduction is the influence of the type of data grouping on inequality measures. Therefore, nonparametric approaches are not strictly preferable to parametric approaches when comparing income inequality in different countries." (SUMMARY IN ENG)