The increasing adoption of mobile platforms and digital textbooks in university classrooms continues to have a profound impact on higher education. Advocates believe that providing students digital textbooks with built-in annotation features and interactive study tools will improve learning by facilitating active reading, a task essential to learning. Thus, several different novel reading-study systems for academic textbooks have surfaced. Standard usability measures, as well as learning and retention tests, are among the common measures of effectiveness for new systems. However, prior research has not included thorough assessment of how well individual tools assist learners in their active reading goals or becoming more effective active readers. To address this, we developed the Active Reading Experience Questionnaire (AREQ), a 29-item survey that prompts learners to report on their active reading strategies for a specific active reading experience. The AREQ is based on widely recommended strategies for effective active reading, and this paper presents results from a study in which the instrument was fully validated. Recommendations for use and future research are also discussed.