William J. Youden

William John Youden, also known as Jack Youden, was an Australian-born American analytical chemist and statistician who formulated new statistical techniques in statistical analysis and in design of experiments. He developed the "Youden square", an incomplete block design developed from a 1937 paper, "Use of Incomplete Block Replications in Estimating Tobacco Mosaic Virus". He also helped to introduce the concept of restricted randomization, which he called constrained randomization. He devised Youden's J statistic as a simple measure summarising the performance of a binary diagnostic test.