AGGREGATION METHODS FOR INTERCOUNTRY COMPARISONS OF PRICES AND REAL VALUES IN AGRICULTURE - A REVIEW AND SYNTHESIS

This paper considers alternative approaches to providing consistent in tercountry comparisons of prices, quantities and productivity in the a gricultural sector. Bilateral index numbers allow price and quantity c omparisons between two countries, whereas multilateral indexes make it possible to construct real values, purchasing-power parities (PPPs) a nd productivity indexes across a larger number of countries at a given point in time. We describe the empirical and theoretical properties o f the most common index numbers. We then examine how empirical results are affected by applying the different multilateral approaches to com pare the real agricultural output of ten European countries and the Un ited States. We provide a set of PPPs for agricultural output which ca n be used for comparing real agricultural output aggregates.