
Owen Lin/Flickr. CC (by-nc-nd)
Four years ago the Walk Free Foundation (Walk Free) published the first ever Global Slavery Index (GSI), with the goal of spurring the international community to action by quantifying human exploitation. For an issue to exist, Bill Gates apparently advised Walk Free’s founder Andrew Forrest, it must be measurable. And if something can be measured, so can the world’s progress be towards eliminating it.