Assessment results collected under low-stakes testing situations are subject to effects of low examinee effort. The use of computer-based testing allows researchers to develop new ways of measuring examinee effort, particularly using response times. At the item level, responses can be classified as exhibiting either rapid-guessing behavior or solution behavior based on the item response time. Most previous research involving the study of response times has been conducted using locally developed instruments. The purpose of the current study was to examine the amount of rapid-guessing behavior within a commercially available, low-stakes instrument. Results indicate that smaller amounts of rapid-guessing behavior exist within the data compared to published results using other instruments. Additionally, rapid-guessing behavior varied by item and was significantly related to item length, item position, and presence of ancillary reading material. The amount of rapid-guessing behavior was consistently very low among various demographic subpopulations. On average, rapid-guessing behavior was observed on only 1% of item responses. Also found was that a small amount of rapid-guessing behavior can impact institutional rankings. (Contains 3 tables, 4 figures and 5 footnotes.)