The objective of the present study was to evaluate the extent to which students who took a computer adaptive test of reading comprehension accounting for testlet effects were administered fewer passages and had a more precise estimate of their reading comprehension ability compared to students in the control condition. A randomized controlled trial was used whereby 529 students in Grades 4-8 and 10 were randomly assigned to one of two conditions, both of whom took a computerized adaptive assessment of reading comprehension. Participants in the experimental condition had ability scores estimated as a function of an item response model, which accounted for item-dependence effects in the reading assessment, whereas control students took a version where item-dependence effects were not controlled. Results indicated that examinees in the experimental condition took fewer passages (average Hedges' "g" = 0.97) and had more reliable estimates of their reading comprehension ability (average Hedges' "g" = 0.60). Findings are discussed in the context of potential time savings in assessment practices without sacrificing reliability.