In 1931 he was appointed assistant statistician at Rothamsted Experimental Station by Ronald Fisher. In 1933 he became head of statistics when Fisher obtained a position at University College London. At Rothamsted he worked on the design of experiments, including contributions to the theory of analysis of variance and originating Yates' algorithm and the balanced incomplete block design.
After the war he worked on sample survey design and analysis. He became an enthusiast of electronic computers, in 1954 obtaining an Elliott 401 for Rothamsted and contributing to the initial development of statistical computing. In 1966 he was awarded a Royal Medal from the Royal Society. He retired from Rothamsted in 1968 and became a Senior Research Fellow at Imperial College.