This paper examines the consistency of two series of aggregate output data in comparing the agricultural performance of60 developing countries. Employing two approaches that take into account the fact that deepening of intermediate goods takes place in agriculture as development proceeds, it is found that, in less than half the country cases tested, the data on gross agricultural output compiled by the US Department of Agriculture and the series on value-added in agriculture .produced by the World Bank are consistent with each other and with the expectation of deepening of intermediate goods. The World Bank's aggregates provide the more optimistic reading of performance of the two series, but neither series indicates that a majority of developing countries have performed adequately in terms of the test of agricultural performance suggested by Johnston and Mellor in 1961.