This paper proposes a new method for ex ante analysis of the poverty impacts arising from policy reforms. Three innovations underlie this approach. The first is the estimation of a global demand system using a combination of micro-data from household surveys, and macro-data from the International Comparisons Project. The second innovation relates to a methodology for postestimation calibration of the global demand system, giving rise to country specific demand systems and an associated expenditure function which, when aggregated across the expenditure distribution, reproduce observed per capita budget shares exactly. The third innovation is use of the calibrated expenditure function to calculate the change in the head-count of poverty, poverty gap and squared poverty gap arising from policy reforms, where the poverty measures are derived using a unique poverty level of utility, rather than an income or expenditure-based measure. We employ these techniques with a demand system for food, other non-durables and services estimated using a combination of 1996 ICP data set and national expenditure distribution data. To illustrate the usefulness of these calibrated models for policy analysis, we assess the impacts of an assumed five percent food price rise as might be following a multilateral trade agreement.