Instructors can see Time on Task by using the Reports. The Proficiency Report (for example) shows an instructor total time spent per student, time spent on chapter per student, and time spent by learning objective. It includes active learning time (i.e. the time spent on answering questions, and working in the eTextbook). Time on task is not available for individual assessments.
Time on task is available in the following reports: Proficiency Report, Productivity Report, Engagement Report.