This paper outlines the methodologicalissues associated with the task of measuring that actualdelivered direct protection or taxation to individualagricultural industries, as well as the direct protection oranti-protection to non-agricultural sectors. It begins witha guide to what elements in principle could be measured.There are two key purposes of the distortion estimates beinggenerated by this project are: 1) to provide a long annualtime series of indicators showing the extent to which priceincentives faced by farmers and food consumers have beendistorted directly and indirectly by own-government policiesin all major developing, transition and high-incomecountries, and hence for the world as a whole; and 2) toattribute the price distortion estimates for each farmproduct to specific border or domestic policy measures, sothey can serve as inputs into various types of partial andgeneral equilibrium economic models for estimating theeffects of those various policies on such things as nationaland international agricultural markets, farm value added,income inequality, poverty, and national, regional andglobal welfare.