The simulator used in this study was the S/NS (Shoot/Not Shoot) Reaction Time Stimulator. The system consists of a computerized movie projector and a standard service weapon retrofitted with a laser emitting device. As the scene unfolds, the officer answering the call must determine what responses are appropriate. Officers must decide if and when to draw the service weapon as well as if and when to discharge the firearm. The computer registers the frame at which the officer unholsters the weapon and the frame at which the officer discharges the firearm. Eight scenarios portrayed by the simulator were used for this study. This study involved the first 56 officers of the Tallahassee Police Department (Florida) scheduled for the training exercise. The data indicate unholstering behavior in 363 incidents and shooting behavior in the 271 "shoot" scenarios. Findings show that a weapon was drawn before a lethal threat materialized in 28 percent of the incidents. Rookies were more likely to display a weapon prematurely than were experienced officers. Although gender differences were not significant, female officers showed a tendency to stay holstered longer than their male counterparts. Unholstering was not affected by race. A premature shooting occurred in 5 percent of the incidents. Overall, officers tended to wait for a very clear indication of suspect intentions. Shooting accuracy declined with the length of time it took to unholster the weapon. Marksmanship eroded with late shooting. Staying too late in the holster was more likely to produce a miss or to risk not being able to return fire once the attack had commenced. Too-late unholsterings were almost twice as likely to produce an officer death as were reactions with a timely or too early draw. 3 tables and 37 references