# Derrick Norman Lawley (1915-2012)

**Derrick Norman Lawley (1915-2012)** was a statistician in the Godfrey Thomson Unit for Educational Research and later Lecturer in Statistics at Edinburgh University from 1948 to 1982.

## Contents

## Biography

The son of an engineer, Lawley was educated at Charterhouse and Clare College, Cambridge, graduating BA in Mathematics in 1937. He was immediately recruited as a statistician in the Godfrey Thomson Unit for Educational Research, based at the Edinburgh Provincial Training Centre (later Moray House College of Education). Here he was not only involved in constructing and standardising the Moray House Tests but, through his work for Sir Godfrey Hilton Thomson (1881-1955), became a recognized authority in the wider field of factor analysis. This not only earned him a DSc but led him to be elected to the Royal Statistical Society in 1946 and Royal Society of Edinburgh in 1948.

In 1946, Lawley was appointed Lecturer in Statistics in the University of Aberdeen, but only a year later Professor Alexander Craig Aitken (1895-1967) persuaded him to assume the same role at Edinburgh University. He joined the Unit of Statistics when it moved from Aberdeen to Edinburgh University in 1966, remaining there until retirement in 1982.

## Research

Lawley published over 60 papers and was a pioneer in various aspects of multivariate statistical inference. He was a pioneer in bringing modern principles of statistical estimation into the structure of factor analysis. In 1943, he published a paper which marked the beginning of item response theory as a measurement theory. With A. E. Maxwell, he co-wrote *Factor Analysis as a Statistical Method* (1963), which remains a standard introductory text for psychometricians and was crucial in earning the subject academic respectablity. His 1968 paper with K. G. Jöreskog, 'New methods in Maximum Likelihood Factor Analysis' was a major methodological advance in an era before computers provided efficient numerical procedures for the maximisation of a complicated likelihood function.

## Archives

- Papers of Godfrey H. Thomson
- Records of the Godfrey Thomson Unit for Educational Research
- Papers of Professor Walter Ledermann