Sex as individual biological characteristic (female or male) is recorded during data collection in censuses, surveys or administrative sources. By comparison to gender differences, which are shaped over by the history of social relations, and change over time and across cultures, biological differences in sex are fixed and unchangeable and do not vary across cultures and overtime. Sex-disaggregated data have the capacity to reveal differences in women’s and men’s lives that are the result of gender roles and expectations. For example, gender may determine differences in education or work for women and men. Statisticians reveal these gender differences by collecting and analysing data on education and work disaggregated by sex as well as other characteristics.