From 1936 onwards Yates (11, 12, 13, 14, 15, 16)has introduced a series of incomplete block designs; the purpose of the designs was to segregate the variation within the complete blocks into that due to differences between and that within the incomplete blocks and at the same time to retain the advantages of the randomized complete blocks. The complete block was divided into incomplete blocks, each containing a portion of the total number of the treatments compared, in such a way that the differences between incomplete blocks could be eliminated from the treatment comparisons.https://lib.dr.iastate.edu/specialreports/1003/thumbnail.jp
