disadvantage (so it is not strictly a measure of equality), and is intended to allow comparative comparison of gender gap across different countries and years. Increased scores over time can be interpreted as the percentage of the inequality between women and men that has been closed. The report examines four critical areas of inequality between men and women in approximately 130 economies around the globe, focusing on economic participation and opportunity, educational attainment, political empowerment and health and survival statistics. GEI and GGP measures are conceptually more broader. GEI focuses on socioeconomic opportunities, but it has been criticized for ignoring underlying causes of gender inequality such as health. GGI is the most comprehensive, through it in turn has been criticized for being too broad. Social Institutions and Gender Index To address the perceived inadequacies of those four indices, in 2007 the OECD Development Centre introduced a Social Institutions and Gender Index (SIGI), a composite indicator of gender equality that solely focuses on social institutions that affect the equality between men and women, as well as on the four dimensions of family code, physical integrity, ownership rights and civil liberties. Social institutions comprise norms, values and attitudes that exist in a society in relation to women. SIGI's authors argue that it is "the only index that focuses on the underlying sources of gender inequality", through they note it is indented to supplement, not replace, the aforementioned other existing measures; they also note that this topic is likely too complex for a single indicator, and recommend a multi-indicator approach for any studies that want to aim to be more comprehensive. The tool has been praised for being a valuable measure for developing countries, but criticized as less applicable for the developed ones. See also Gender Parity Index References Further reading Gender equality International rankings Statistical data sets