PLANNING a piece of research in any field involves a certain order of procedure. This will in general have three parts (1) a statement of the objectives, (2) a description of the experiment covering such points as the selection of experimental treatments, decision regarding accuracy of measurements, selecting the experimental units, determining the general condition under which the test shall be made and specifying the experimental design and (3) an outline of the method of the analysis of the results. Methods for increasing the accuracy of experiments may be classified into three types: (1) increasing the size of the experiment, (2) refining the technique and (3) handling the experimental material so that the effects of variability are reduced. This may be done by careful selection of the material, by taking additional measurements that provide information about the material or by skillful grouping of the experimental units into an efficient plan. Using the ideas of confounding and grouping of the experimental units as the criteria, the various types of experimental designs have been classified. The following types of designs were presented, illustrated and discussed: (1) Complete block designs including completely randomized, randomized blocks, latin square and cross-over designs. TABLE 1-ANALYSES OF FIELD EXPERIMENTS, 1942-1948. NORTH CAROLINA AGRICULTURAL EXPERIMENT STATION.