Uniformity data for eight different crops were studied with the object of making comparisons of the efficiency of Incomplete and Randomized Block methods. Altogether 26 different comparisons were made.In general the Incomplete Block method gives increases in efficiency, such increases being partially correlated with soil heterogeneity. If the field is very uniform there may be a loss in efficiency but this is rather unlikely on the average field and with careful planning of the experiment. The increases in efficiency due to the use of Incomplete Block methods would appear to vary on the average from 20 to 50%. In view of the greater adaptability of these methods to irregularly shaped fields, in addition to greater efficiency, their use can be generally recommended.The relative efficiency of Incomplete and Complete Block methods was studied in relation to the size and shape of plots and blocks. The former method gives the greatest gains in efficiency when the Incomplete Blocks are nearly square and are made up of long narrow plots.