Delta employees protest human trafficking. Delta News Hub/Flickr. CC (by)
In November 2014, the Walk Free Foundation launched the second edition of their flagship Global Slavery Index. The press release for the launch declared the index to be ‘the most accurate and comprehensive measure of the extent and risk of modern slavery’, building upon an ‘improved methodology’ including random-sample surveys from 19 countries. This emphasis on methods was significant, because the inaugural 2013 index had been repeatedly criticised for using unreliable, incomplete and inappropriate data. Despite this focus on improved methods, the second version of the index once again attracted sustained criticism. One of the sharpest challenges came from Anne Gallagher, who reported that the index contained ‘critical errors of fact and logic’.
While Walk Free wouldn’t necessarily agree with these exact sentiments, they have nonetheless acknowledged that the index suffers from a number of limitations. These problems are not unique to the slavery index, but also apply to global estimates of slavery and trafficking more broadly. It is not our intention to revisit these specific methodological issues here. Instead, we are interested in why non-governmental organisations (NGOs) such as Walk Free have continued to generate statistical information that they know to be highly suspect, and why numerous third parties have continued to reproduce these types of statistical claims despite also knowing the same.
