138 \ Global Youth Development Index and Report 2016 Annex 2  Methodology of the Youth Development Index Any composite index is constructed from an initial set of disparate data. These datasets measure different aspects of the index that are incommensurable by themselves. To take raw country data and combine them into a composite index requires a number of procedural steps. The general process for creating a composite index follows the following stages: • sourcing and collecting raw data • filling or imputing data gaps • banding • weighting • aggregating. This annex will explain step by step the process of constructing the YDI. A2.1  Sourcing and collecting raw data The YDI is designed to measure youth development based on the following five domains: • • • • • Domain 1: Education Domain 2: Health and Well-being Domain 3: Employment and Opportunity Domain 4: Political Participation Domain 5: Civic Participation These domains and likely indicators were decided and agreed through consultation with the YDI Technical Advisory Committee. To be able to gauge youth development within each country in these domains, 18 indicators were sourced that measure an aspect of one of the five domains, as shown in Tables A2.1 to A2.5. Table A2.1  YDI indicators for the Education domain, 2010–15 Code Indicator Source Latest year Global coverage of countries Number of countries with only one single data point in the YDI D1.1 Enrolment in secondary education (gross) UNESCO 2015 177 15 D1.2 Literacy rate (15–24) UNESCO 2015 151 34 D1.3 Digital native rate International Telecommunication Union 2013 178 178 Table A2.2  YDI indicators for the Health and Well-being domain, 2010–15 Code Indicator Source Latest year Global coverage of countries Number of countries with only one single data point in the YDI D2.1 Youth mortality rate Institute for Health Metrics and Evaluation 2013 184 0 D2.2 Drug abuse rate by YLL (15–29) GBD 2013 184 0 D2.3 HIV rate (15–24) World Bank 2013 108 1 D2.4 Alcohol abuse rate by YLL (15–29) GBD 2013 184 0 D2.5 Mental disorder rate by YLL (15–29) GBD 2013 184 0 D2.6 Score on Global WellBeing Index (15–29) Gallup World Poll 2014 144 23