Abstract: Since the time of Fisher and Yates, intense combinatorial study of balanced incomplete block designs has led to a great many designs with the same numbers of treatments, blocks, and block size. While the basic analysis does not differentiate among different BIBDs with the same parameters, they do differ in their capacity to withstand loss of experimental material. Competing BIBDs are compared here for their robustness in terms of average loss and worst loss. A table of most robust BIBDs is compiled. Two useful criteria are minimum intersection aberration and minimum efficiency aberration.
Key words and phrases: Balanced incomplete block design, design efficiency, efficiency aberration, intersection aberration, missing data, robustness.