What we have learned about psychological tests from an I/O perspective is that some tests are useful in forecasting job success and others are not. As an entire class of predictors, psychological tests have been moderately predictive of job performance. Yet some authors believe that, all things considered, psychological tests have outperformed all other types of predictors across the full spectrum of jobs. Single-validity coefficients greater than .50 are ass unusual today as they were in the early years of testing. Although test validity coefficients are not as high as we would like, it is unfair to condemn tests as useless. Also, keep in mind that validity coefficients are a function of both the predictor and the criterion. A poorly defined and constructed criterion will produce low validity coefficients no matter what the predictor is like. Because of the limited predictive power of tests, psychologists have had to look elsewhere for forecasters of job performance. The balance of this chapter will examine other predictors that psychologists have investigated