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The Global Slavery Index is an annual ranking of slavery conditions in countries (2013 ''n'' = 162, 2014 n = 167) world wide published by the Walk Free Foundation.〔(【引用サイトリンク】 title=Global Slavery Index )〕 In 2013, the first Global Slavery Index included information about (1) prevalence (2) vulnerability and (3) country level national responses. In 2013 the Index itself is calculated based on a combined measure of three factors: 1) estimated prevalence of modern slavery by population (using primary and secondary data sources); 2) a measure of child marriage; and 3) a measure of human trafficking in and out of a country. In 2014, the methodology was substantially updated.〔(【引用サイトリンク】 title=Global Slavery Index Methodology )〕 The 2014 Global Slavery Index includes 3 data points for each country, on (1) national estimates of prevalence of modern slavery (2) vulnerability measures (3) assessment of strength of government responses.〔(【引用サイトリンク】 title=Government Response )〕 The Index has been pioneering the use of random-sampled, nationally representative surveys to estimate prevalence at the national level. This included commissioning 7 such surveys in 2014; and a further 19 surveys through Gallup World Poll in 2015. The 2014 Index includes country studies with policy recommendations for many countries including: Australia, Pakistan, India, Brazil, the United Kingdom, the United States, Qatar, and others. ==Calculation== The 2014 Global Slavery Index includes data on 3 key variables: (1) prevalence of modern slavery in each country (2) vulnerability and (3) government responses to modern slavery. The methodology is written up in detail in a (methodology paper ). The first of these factors, the prevalence estimates were derived, using a statistical process known as extrapolation. In 2015, Joudo Larsen, Bales and Datta published an article that describes the extrapolation process, and provides a test of it. Writing in (Significance ), the magazine of the UK Royal Statistics Society, Joudo Larson et al note that extrapolation in the 2014 Global Slavery Index involved several steps: - Clustering: Countries were grouped into 7 clusters, based on an analysis of how similar or different they are, when factors relevant to vulnerability of enslavement are taken into account. The data on vulnerability included variables on five dimensions: state stability, social discrimination, presence or absence of human rights protections, economic and social development, and presence of governmental slavery policy. The groups were chosen by a K-means clustering algorithm, deciding on the final cluster out of a dozen trials that had the highest pseudo-F score. Seven groups were chosen as there were seven prevalence surveys that used the same instruments and data collection methods, and ideally, each survey could be applied to a unique group. - Extrapolation: survey data on prevalence that was available for each cluster (expressed as a percentage of the population) was then used as the basis of the estimation for other countries within that same cluster. A slightly different method was followed for 'cluster 1', which involved mostly European and highly developed countries. This is discussed further below in the article by Bales and Datta, - National level adjustments were done by hand on a country by country basis, reflecting considerations such as geography. This resulted in a prevalence estimate for each country calculated as a proportion of the total population that was enslaved within that country. For all 167 countries this produced a total global estimate in 2014 of 35.8 million enslaved people. Writing in 2015, Larsen et al note that newer 2015 survey estimates now allow a comparison and test of at least some of the 2014 extrapolated estimates. This is important for checking the validity of the earlier results and the continued application and use of this methodology. The comparisons suggest that extrapolation, while not perfect, is a useful and valid method - as all but one of the extrapolation estimates of prevalence of slavery (considered as a percentage within a national population) fall within one percentage point of the estimates arrived through random sample surveys 〔Jacqueline Joudo Larsen, Monti Narayan Datta and Kevin Bales, "Modern Slavery", Significance, Volume 12, Issue 5, pages 22–43, October 2015〕 Data from the Global Slavery Index is used in the (Ibrahim Index of African Governance ) data portal (http://www.moibrahimfoundation.org/iiag/data-portal/) In their article "Slavery in Europe: Part 1, Estimating the Dark Figure", Monti Datta and Kevin Bales demonstrate the statistical techniques applied to the estimation of the dark figure of the prevalence of modern slavery across Europe.〔 These same techniques are applied to a dataset that includes random survey sampling (where possible), secondary source estimates, a process of extrapolation, and a country level adjustment to determine the prevalence of people in modern slavery around the world in the Global Slavery Index. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Global Slavery Index」の詳細全文を読む スポンサード リンク
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