The revised methodology has been developed by the ILO in close collaboration with a Peer Review Group composed of four members of the academic community who are experts in the subject of forced labour and human trafficking. It follows the same basic two-stage approach used for the 2005 estimate, but incorporates certain improvements derived from ILO’s own experience in the period since 2005, the availability of new primary data sources, feedback received from external experts on the 2005 methodology, and suggestions made by the ILO’s statistical consultants and the peer reviewers.