Countries with a higher level of gender inequality tend to have more inequality in the ratio of men in prison to women in prison. The United Nations’ Gender Inequality Index (GII) compares male and female parliamentary representation, labor force participation, and attainment of secondary and higher education. It also includes measures of maternal mortality and adolescent female fertility relative to particular reference norms. The GII, like development policy generally, doesn’t consider male and female imprisonment. It doesn’t recognize large, worldwide inequality in the ratio of men in prison per women in prison.
The United Nations’ Gender Inequality Index correlates positively but imperfectly with inequality in the prisoner sex ratio. Moving from the 2011 median country-value for the GII to the 75th percentile is associated with a 15% increase in the ratio of males to females in prison. The prisoner sex ratio, however, is 56% greater at its 75th percentile relative to its median value. The GII and the prisoner sex ratio are different but correlated measures of gender inequality.
Gender inequality in the sex ratio of prisoners concerns the most directly and personally punishing outcomes of public policy. The GII, in contrast, encompasses elite statuses: the sex ratio in parliamentary representation and in degrees received in higher education. The prisoner sex ratio is a more appropriate focus for welfare concern about gender inequality in human development.
The Gender Inequality Index has more uncertainty in its measurement and is more complicated and difficult to understand than is the sex ratio of prisoners. Measuring labor force participation requires a country-wide survey. Measuring maternal mortality and adolescent female fertility requires compiling nation-wide birth and death data with record-specific information on sex, age, and cause of death. Measuring the level of formal education in the population requires a long-form national survey. Understanding the actual calculation of the GII requires the ability to parse complicated mathematical formulas and some understanding of index-number theory. A specific value of the GII has no specific meaning to most persons. The sex ratio of prisoners, in contrast, requires collecting information only from political bodies authorized to imprison persons. The prisoner sex ratio is simple to calculate and easy to understand.
Just as for inequality in economic growth generally, the weight of welfare concern about gender inequality across population groups is a matter of justice. More concern for the parliamentary sex ratio than for the prisoner sex ratio indicates lack of concern for the poor.