In the preceding chapter it was shown that the officially published data on acreage under cultivation are mostly underestimates and those on yield per acre overestimates. Also discussed was how the revision of the official figures on acreage in the light of the data available from the Ishaque Report (1944/45) is likely to provide more reliable estimates of the agricultural trends in Bengal. The purpose of the present chapter is to analyse the percentage rates of change in crop output in the two series and their determinants – acreage and yield per acre. Trend rates of other provinces are also presented to indicate the comparative position of Bengal and, thus, to emphasise the greater rationality of the trends in the revised series. In order to bring out more clearly how the change in output, both at the provincial and regional level, was being influenced by the trends in acreage and yield, the three variables – output, acreage and yield – should be discussed simultaneously. But clearly such a mode of presentation would make the analysis more complicated than is desirable. Therefore, the percentage rates of change in the three items are presented separately. This is done first for all-Bengal and then individually for the five regions. The emphasis of the present chapter is on all the 13 crops taken together and then on the two groups of food crops and cash crops, though occasional references are made to some of the individual crops as well. In order to facilitate the interpretation of the differences in the percentage rates of change at the regional level the relative importance of these groups of crops in each region is also indicated.