The ILO's Special Action Programme to Combat Forced Labour (SAP-FL) and the Statistical Development and Analysis Unit of the ILO's Policy Integration Department have pooled their efforts and resources to confront the methodological challenge of estimating global forced labour. The ILO also relied on external advice. On 28 and 29 April 2003, a consultation meeting was held at the ILO in Geneva with participants from academia, international organizations, NGOs, and governments. The meeting brought together statisticians, specialists in quantitative methods, and recognized international experts of forced labour. After this meeting, the estimation project carried on for a period of nearly two years. Today the ILO publishes its first ever estimate of forced labour in the world, with indications of its regional distribution and broad forms. The main results are published in the Director General's 2005 Global Report called "A Global Alliance against Forced Labour". The present technical document provides a detailed account of the methodology used in the estimate. It also includes a thorough evaluation of the results, with calculation of margins of error and comparison with external sources.More information about human trafficking on the website of ILO.