Isoperformance and Personnel Decisions

Abstract

Isoperformance curves are contour lines or surfaces that trace all combinations of two or more determinants that suffice to produce a specified level of performance? hence the term isoperformance. When the determinants are aptitude and training time or time on the job, an isoperformance curve allows one to identify individuals who have sufficient aptitude for the work that they can be expected to reach a specified standard of performance in a specified length of time. This paper discusses isoperformance in the personnel selection and classification literature and then develops and illustrates the uses of isoperformance curves in personnel decisions. The idea of aptitude sensitivity is introduced, and the relationship between this idea and predictive validity is explained. The paper also indicates how isoperformance can be used to detail trade-offs among training time, the minimum qualifying score, attrition rate, quotas, and the specified level of criterion performance. Isoperformance finds direct application in the multiple-job assignment problem, exemplified by the choice of which recruit to send to which training school in the military services.