The emphasis on a data gathered first-hand,combined with a cross-cultural perspective brought to the analysis of cultures past and present ,makes this study a unique and distinctly important social science.
Social science methodologies had to be adapted to a discipline governed by the primacy of historical sources rather than the imperatives of the contemporary world.
In general,the tests work most effectively when the qualities to be measured can be most precisely defined and least effectively when what is to be measured or predicted cannot be well defined.