12 \ Global Youth Development Index and Report 2016 areas in which collection of data on young people needs to be strengthened or expanded. The YDI makes it possible to compare the status and well-being of young people in different countries and regions. It is a tool and resource to help policymakers, researchers, development practitioners, young people and others see how young people are faring in absolute and relative terms, identify successes and achievements that could provide provide inspiration to others, and where policies, programmes and investment need to be targeted in order to improve the quality and state of youth development. The YDI is not an end in itself. Its primary goal is to generate a conversation among key stakeholders, help policymakers identify priority areas for intervention and reform, empower young people with information, and provide an evidence base to those who need data to guide their investment decisions and advocacy efforts. The inaugural iteration of the YDI, published by the Commonwealth Secretariat in 2013, was the first ever attempt at capturing the multidimensional properties that indicate progress in youth development at the country level. This report provides the results and findings from the second iteration of the YDI, which is based on an updated methodology. In combination, the analysis provides a snapshot of progress in youth development based on the latest available data, with a time series going back to 2010. The new YDI reflects improvements in methodology and data that have made it possible to build a more sophisticated and nuanced picture of youth development across the world. While this index is not comparable with the 2013 iteration, datasets sourced retrospectively in line with the revised methodology make it possible in this iteration to compare youth development levels in 2010 and 2015. A discussion on improvements made in the methodology can be found in Annex 2. The various age definitions of youth used by different agencies posed a significant challenge in the development of the YDI. As a consequence, indicators included in the YDI unavoidably cover slightly different age cohorts. Adding to this definitional ambiguity is the fact that certain sub-categories considered important to youth development also relate to smaller and different age cohorts. For example, data on teenage pregnancy in the YDI relate only to 13–19-year-olds. 1.6 What does the Youth Development Index measure? The YDI measures five distinct domains or key aspects of youth development: Education, Health and Well-being, Employment and Opportunity, Political Participation and Civic Participation. The YDI uses 18 indicators in total, grouping between two and six indicators in each domain, as shown in Table 1.2, and uses globally recognised data sources. 1.7 How should the Youth Development Index be interpreted? The YDI score is a number between 0 and 1. For a country to receive a perfect score of 1, it would represent the highest possible level of youth development attainable, with 0 reflecting little to no youth development. This scoring system is the same as the one that underpins the HDI produced by the UNDP’s Human Development Report Office (HDRO). In some cases, countries may be separated by very small differences in the scoring that, because of the number of countries in the index (183), may give the impression of greater divergence than might actually be the case. It is also useful to consider whether a country is at a ‘very high’, ‘high’, ‘medium’ or ‘low’ level of youth development, as this categorisation reflects unambiguously the position of a country on a spectrum stretching from ‘relatively good’ to ‘relatively poor’. (The categories are explained in more detail in Chapter 2.) 1.8 The basis for selecting domains and indicators for the Youth Development Index The domains that constitute the YDI were selected on the basis of their importance to and impact on the development of young people. Youth development is multidimensional and many factors are at play during this period between childhood and full adulthood in any person’s life. Evidence grounded in research makes it clear that some of these factors play a more important part in the lives of young people than others. Thus, based on the evidence and also the availability of data, education,