The effects of alcohol, task difficulty, and incentives on a drill press simulation were examined. On four nonconsecutive days the subject received four alcohol levels, one level per day. The levels were: 0.00%, 0.03%, 0.06%, and 0.09% blood alcohol concentration (BAC). The drill press simulation task consisted of placing a drill probe alternately between two holes in a metal plate. For every level of alcohol, each subject received eight levels of task difficulty which were varied by changing the hole size and distance between holes. Task difficulty was in units of bits of information ranging from two to nine and was derived from a portion of Welford's (1968) version of Fitts' Law. For every level of task difficulty each subject received two levels of incentive: productivity and accuracy which were enforced by monetary rewards.

The subject's response was measured by hits and misses. A Hit was defined as placing the metal drill probe in either of two holes in the top metal plate of the workpiece without touching the plate. A miss was defined as a contact of the probe with the top plate.

Except for the effect of alcohol on misses, there were significant main effects of alcohol, task difficulty, and incentive for both hits and misses. There were significant interactions between alcohol and task difficulty for hits, and for incentive and task difficulty for both hits and misses.