Test-taking experience is a consequence of the interaction between students and assessment properties. We define a new notion, rapid-pacing behavior, to reflect two types of test-taking experience -- disengagement and speededness. To identify rapid-pacing behavior, we extend existing methods to develop response-time thresholds for individual items based on empirical patterns of response time and response accuracy. An analysis procedure is proposed to compare the extent of rapid-pacing behavior across testing formats. We also present a case study using datasets from an educational survey assessment of mathematics. A large-scale randomized experiment was conducted involving two testing formats (linear and multistage) for U.S. 8th-grade students. Results suggest that using multistage testing instead of linear testing has differential impact on test-taking experience across performance levels. The lower performers appear more engaged when presented with items better targeted to their proficiency, whereas the higher performers experience more time pressure when presented with more difficult items.