Test Length and Decision Quality in Personnel Selection: When Is Short Too Short?

Personnel selection shows an enduring need for short stand-alone tests consisting of, say, 5 to 15 items. Despite their efficiency, short tests are more vulnerable to measurement error than longer test versions. Consequently, the question arises to what extent reducing test length deteriorates decision quality due to increased impact of measurement error. A distinction was made between decision quality at the group level and the individual level. Using simulations, we found that short tests had a large negative impact on individual-level decision quality, in particular for selecting suited candidates when base rates or selection ratios are low. Negative effects on group-level decision quality were smaller than those for individual-level decision quality. Results were similar for dichotomous-item tests and rating-scale tests, and also for top-down and cut-score selection.