Validating Lanchester’s square law and other attrition models

This article addresses the question of validating the homogeneous Lanchestrian square law of attrition by the use of historical data (and by extension, other attrition models). Validating an attrition model means testing that model against reality. In this case, Lanchester’s square law is tested against the data from the Inchon-Seoul campaign of the Korean War. The data are examined using three analysis techniques: linear regression, the Akaike Information Criterion, and Bozdogan’s Consistent AIC. The data do not fit the assumption of a single, constant coefficient, homogeneous square law battle. The data do fit a set of three such battles (a new one every six or seven days); however, the data fit three constant-casualty-model battles just as well. The homogeneous Lanchester square law cannot be regarded as a proven attrition algorithm for warfare; however, the square law cannot be regarded as disproved either. Data on more battles are required to validate the square law or any other proposed attrition law.