This study reviewed and summarized the literature on the use of written tes
ts in the selection of firefighters using a sample of 13,418 individuals dr
awn from 101 samples. For the prediction of job performance, cognitive test
s showed substantial validity (.42), although mechanical comprehension test
s showed even higher validity (.54). However, the best prediction was obtai
ned by tests which were composites of cognitive and mechanical predictors (
.56). Training criteria was best predicted by cognitive measures (.77), alt
hough mechanical comprehension predictors also showed substantial predictio
n value (.62). Tests which were composites of cognitive and mechanical meas
ures showed validities equal to that of cognitive measures (.77).