Measuring the global gender gap
The methodology of the Index has remained stable since its original conception in 2006, providing a basis for robust cross-country and time-series analysis. This year’s edition introduces an updated threshold for estimating gender parity in earned income, adjusting the income level cap to better reflect contemporary costs of living and bringing the Index in line with the latest thinking and methodology of statistical reports by the United Nations and others. A detailed discussion of this adjustment is provided in Appendix D.
Three underlying concepts
There are three basic concepts underlying the Global Gender Gap Index, forming the basis of how indicators were chosen, how the data is treated and the scale used. First, the Index focuses on measuring gaps rather than levels. Second, it captures gaps in outcome variables rather than gaps in input variables. Third, it ranks countries according to gender equality rather than women’s empowerment. These three concepts are briefly outlined below. For a description of how these concepts are captured by the construction techniques used in the creation of the Index, please see the Construction of the Index section below.
Gaps vs. levels
The Index is designed to measure gender-based gaps in access to resources and opportunities in countries rather than the actual levels of the available resources and opportunities in those countries. We do this to disassociate the Global Gender Gap Index from countries’ levels of development. In other words, the Index is constructed to rank countries on their gender gaps not on their development level. For example, rich countries, generally speaking, are able to offer more education and health opportunities to all members of society, although this is quite independent of the gender-related gaps that may exist within those higher levels of health or education. The Global Gender Gap Index rewards countries for smaller gaps in access to these resources, regardless of the overall level of resources. Thus, in the case of education, the Index penalizes or rewards countries based on the size of the gap between male and female enrolment rates, but not for the overall levels of education in the country.
Outcomes vs. inputs
The second basic concept underlying the Global Gender Gap Index is that it evaluates countries based on outcomes rather than inputs or means. Our aim is to provide a snapshot of where men and women stand with regard to some fundamental outcome indicators related to basic rights such as health, education, economic participation and political empowerment. Indicators related to country-specific policies, rights, culture or customs—factors that we consider “input” or “means” indicators—are not included in the Index, but they are discussed further in the analytic sections of this chapter, as well as being featured in the Report’s Country Profiles. For example, the Index includes an indicator comparing the gap between men and women in high-skilled jobs such as legislators, senior officials and managers (an outcome indicator) but does not include data on the length of maternity leave (a policy indicator). This approach has contributed significantly to the Index’s distinctiveness over the years and, we believe, continues to provide the most objective basis for discussing underlying contextual factors.
Gender equality vs. women’s empowerment
The third distinguishing feature of the Global Gender Gap Index is that it ranks countries according to their proximity to gender equality rather than to women’s empowerment. Our aim is to focus on whether the gap between women and men in the chosen indicators has declined, rather than whether women are winning the so-called “battle of the sexes.” Hence, the Index rewards countries that reach the point where outcomes for women equal those for men, but it neither rewards nor penalizes cases in which women are outperforming men on particular indicators in some countries. Thus, a country that has higher enrolment for girls rather than boys in secondary school will score equal to a country where boys’ and girls’ enrolment is the same.
The four subindexes
The Global Gender Gap Index examines the gap between men and women in four fundamental categories (subindexes): Economic Participation and Opportunity, Educational Attainment, Health and Survival and Political Empowerment. Table 1 displays all four of these subindexes and the 14 different indicators that compose them, along with the sources of data used for each.
Economic Participation and Opportunity
This subindex contains three concepts: the participation gap, the remuneration gap and the advancement gap. The participation gap is captured using the difference between women and men in labour force participation rates. The remuneration gap is captured through a hard data indicator (ratio of estimated female-to-male earned income)1 and a qualitative indicator gathered through the World Economic Forum’s Executive Opinion Survey (wage equality for similar work). Finally, the gap between the advancement of women and men is captured through two hard data statistics (the ratio of women to men among legislators, senior officials and managers, and the ratio of women to men among technical and professional workers).
This subindex captures the gap between women’s and men’s current access to education through ratios of women to men in primary-, secondary- and tertiary-level education. A longer-term view of the country’s ability to educate women and men in equal numbers is captured through the ratio of the female literacy rate to the male literacy rate.
Health and Survival
This subindex provides an overview of the differences between women’s and men’s health through the use of two indicators. The first is the sex ratio at birth, which aims specifically to capture the phenomenon of “missing women”, prevalent in many countries with a strong son preference. Second, we use the gap between women’s and men’s healthy life expectancy. This measure provides an estimate of the number of years that women and men can expect to live in good health by taking into account the years lost to violence, disease, malnutrition or other relevant factors.
This subindex measures the gap between men and women at the highest level of political decision-making through the ratio of women to men in minister-level positions and the ratio of women to men in parliamentary positions. In addition, we include the ratio of women to men in terms of years in executive office (prime minister or president) for the last 50 years. A clear drawback in this category is the absence of any indicators capturing differences between the participation of women and men at local levels of government. Should such data become available at a globally comparative level in future years, it will be considered for inclusion in the Index.
Construction of the Index
The overall Global Gender Gap Index is constructed using a four-step process, outlined below. Some of the indicators listed in Table 1 require specific construction or modification in order to be used in the Index. For further information on the indicator-specific calculations, please refer to the User’s Guide: How Country Profiles Work section in Part 2 of this Report.
Convert to ratios
Initially, all data is converted to female-to-male ratios. For example, a country with 20% of women in ministerial positions is assigned a ratio of 20 women to 80 men, thus a value of 0.25. This is to ensure that the Index is capturing gaps between women and men’s attainment levels, rather than the levels themselves.
Truncate data at equality benchmark
As a second step, these ratios are truncated at the “equality benchmark.” For all indicators, except the two health indicators, this equality benchmark is considered to be 1, meaning equal numbers of women and men. In the case of the sex ratio at birth, the equality benchmark is set at 0.944.2 and the healthy life expectancy benchmark is set at 1.06.3 Truncating the data at the equality benchmarks for each assigns the same score to a country that has reached parity between women and men and one where women have surpassed men.
The type of scale chosen determines whether the Index is rewarding women’s empowerment or gender equality.4 To capture gender equality, two possible scales were considered. One was a negative-positive scale capturing the size and direction of the gender gap. This scale penalizes either men’s advantage over women or women’s advantage over men, and gives the highest points to absolute equality. The second choice was a one-sided scale that measures how close women are to reaching parity with men, but does not reward or penalize countries for having a gender gap in the other direction. We find the one-sided scale more appropriate for our purposes, as it does not reward countries for having exceeded the parity benchmark. However, disparities in either direction are recorded in the Country Profiles.
Calculate subindex scores
The third step in the process involves calculating the weighted average of the indicators within each subindex to create the subindex scores. Averaging the different indicators would implicitly give more weight to the measure that exhibits the largest variability or standard deviation. We therefore first normalize the indicators by equalizing their standard deviations. For example, within the Educational Attainment subindex, standard deviations for each of the four indicators are calculated. Then we determine what a 1% point change would translate to in terms of standard deviations by dividing 0.01 by the standard deviation for each indicator. These four values are then used as weights to calculate the weighted average of the four indicators.
This way of weighting indicators allows us to make sure that each indicator has the same relative impact on the subindex. For example, an indicator with a small variability or standard deviation, such as primary enrolment rate, gets a larger weight within the Educational Attainment subindex than an indicator with a larger variability, such as tertiary enrolment rate. Therefore, a country with a large gender gap in primary education (an indicator where most countries have achieved near-parity between women and men) will be more heavily penalized. Similarly, in the case of the sex ratio indicator (within the Health and Survival subindex), where most countries have a very high sex ratio and the spread of the data is small, the larger weight will penalize more heavily those countries that deviate from this value. Table 2 displays the values of the weights used.5
Calculate final scores
For of all subindexes, the highest possible score is 1 (parity) and the lowest possible score is 0 (imparity), thus binding the scores between inequality and equality benchmarks.6 An un-weighted average of each subindex score is used to calculate the overall Global Gender Gap Index score. Similar to subindex scores, this final value ranges between 1 (parity) and 0 (imparity), thus allowing for comparisons relative to ideal standards of equality in addition to relative country rankings.7 The parity and imparity benchmarks remain fixed across time, allowing the reader to track individual country progress in relation to an ideal standard of equality. Furthermore, the option of roughly interpreting the final Index scores as a percentage value that reveals how a country has reduced its gender gap should help make the Index more intuitively appealing to readers.8
1 Following a methodology originally developed by the United Nations Development Programme (UNDP), the Global Gender Gap Index estimates the average income earned by women, relative to income earned by men, in a calculation that takes into account a country’s GDP per capita (US$), the share of women and men in the labour force, and their mean nominal wages. To account for globally rising income levels, beginning with this year’s edition of the Report, the maximum income value considered in the calculation has been capped at US$75,000 per capita. This follows UNDP’s own adjustment of the methodology in line with findings by Kahneman and Deaton that suggest there is little additional gain in human well-being from annual income beyond US$75,000. In previous editions of the Global Gender Gap Index, this cap was US$40,000. Since 2011, the US$ 40,000 cap had lost some its ability to discern the level of gender-based income disparities among high-income nations such as the Nordics, the United States and the member states of the Gulf Cooperation Council. For a full overview of this year’s methodology change, refer to Appendix D. For a more detailed discussion of the assumptions behind the Estimated earned income indicator, refer to: Kahneman and Deaton, High income improves evaluation of life but not emotional well-being, and Human Development Report 2015, UDNP; Technical Notes and UNDP, “Frequently Asked Questions: Gender Development Index (GDI)”, available at: http://hdr.undp.org/en/faq-page/gender-development-index-gdi (accessed October 2016).
2 This ratio is based on what is considered to be a “normal” sex ratio at birth: 1.06 males for every female born. See: Klasen and Wink, “Missing Women: Revisiting the Debate”.
3 This ratio is based on the standards used in the UNDP’s Gender-Related Development Index, which uses 87.5 years as the maximum age for women and 82.5 years as the maximum age for men.
4 A first attempt to calculate the gender gap was made by the World Economic Forum in 2005; see Lopez-Claros and Zahidi, Women’s Empowerment: Measuring the Global Gender Gap. The 2005 Index, which was attempting to capture women’s empowerment, used a “feminist” scale that rewarded women’s supremacy over men (highest score is assigned to the country with the biggest gap in favour of women).
5 As in previous editions of the Index, weights derived for the 2006 Index were used again this year to allow for comparisons over time. They may be revised in future editions to reflect the evolution of the gender gap over the past decade.
6 This is not strictly accurate in the case of the Health and Survival subindex, where the highest possible value a country can achieve is 0.9796. However, for purposes of simplicity, we will refer to this value as 1 throughout the chapter and in all tables, figures and Country Profiles.
7 Because of the special equality benchmark value of 0.9796 for the Health and Survival subindex, it is not strictly accurate that the equality benchmark for the overall Index score is 1. This value is in fact (1 + 1 + 1 + 0.9796) / 4 = 0.9949. However, for purposes of simplicity, we will refer to the overall equality benchmark as 1 throughout the chapter and in all tables, figures and Country Profiles.
8 Since the indicators in the subindexes are weighted by the standard deviations, the final scores for the subindexes and the overall Index are not a pure measure of the gap vis-à-vis the equality benchmark, and therefore cannot be strictly interpreted as percentage values measuring the closure of the gender gap. However, for ease of interpretation and intuitive appeal, we will be using the percentage concept as a rough interpretation of the final scores.