[Excerpt] Workers who are assigned to the same job and paid the same wage often differ greatly in productivity. Coefficients of variation of individual productivity in specific jobs based on hard measures of physical output average .144 for factory operatives, .35 for sales clerks and .28 for craft workers (Hunter, Schmidt and Judiesch 1988). This paper examines whether and to what extent variations in productivity (and other job outcomes) across workers doing the same job at the same firm can be predicted by information on the background and training of the individual worker.