The data comprising the domains of the Gender Index come from different content areas in a variety of disciplines. For this reason they cannot be used collectively for the presentation of an overall situation at any given time. However, the logic that guides the Index gives it the ability to indicate a general trend that is more comprehensive than the data displayed in each area separately. The grouping of data and their expression as a single numeric value make it possible to simultaneously examine the changes that have taken place in the gender inequality situation over the years in many areas. Development of the Gender Index involved creating the simplest possible platform for estimation, into which more indicators and domains could be added to reflect more and more quantitative manifestations of gender inequality—separately and comprehensively. To select indicators with the capacity to express gender inequality, we held extensive talks with members of the steering committee and with feminist organizations. We compiled a list of the dozens of social manifestations of gender inequality, and sought indicators that had internal validity and lent themselves to the quantitative expression of said manifestations. The indicators are variables that are monitored consistently each year, in the same manner and by the same executors. The next step was matching the indicators that define gender inequality with the existing indicators. We found dozens of indicators, grouped them, and then used factor analysis to determine their relevance to gender inequality. At the end of this screening process, we were left with fifty indicators that are not overly correlated with one another but that correlate to the first predictive factor established by the factor analysis. The first year for which we have data for all indicators that met the criteria is 2004, and therefore this is the first year of measurement. The selected indicators were converted into the ratio between the rate of men and the rate of women in a manner that reflects increasing gender inequality. Indicators that were not ratios were standardized, and some are presented as a proportion of the population. All the indicators in each of the Index’s ten domains were measured and their averages calculated independently. In each domain we squared the score, totaled, and divided by ten to obtain the overall Gender Index value for the given year. This formula—that is, the squaring of the average value of each domain—is based on the OECD’s Social Institutions and Gender Index (SIGI).
The Gender Index is based on data obtained from several official sources, chief among them Israel’s Central Bureau of Statistics. Because the Index monitors changes in gender inequality, it is imperative that it use stable data sets gathered in the same manner each year. Therefore, we also used data from the National Insurance Institute—the report on poverty and social gaps, the report on average wage and income, by locale and other economic variables—and the Knesset Research and Information Center, which obtains its data from the police, the Health Ministry, the Welfare Ministry, and the Association of Rape Crisis Centers in Israel. Another source of data pertaining to segregation in the labor market is the Civil Service Commission’s Department for the Advancement and Integration of Women.