This paper reports on the use of simulation when a randomization procedure is used to control item exposure in a computerized adaptive test for certification. We present a method to determine the optimum width of the interval from which items are selected and we report on the impact of relaxing the interval width on measurement precision and item exposure. Results indicate that, if the item bank is well targeted, it may be possible to widen the randomization interval and thus reduce item exposure, without seriously impacting the error of measure for test takers whose ability estimate is near the pass point.