Undoubtedly the greatest single source of error in group test administration is incorrect timing of tests that require a time limit. Examiners must allot sufficient time for the entire testing process: setup, reading instructions out loud, and the actual test taking by examinees. Allotting sufficient time requires foresightful scheduling. For example, in many school settings, children must proceed to the next class at a designated time, regardless of ongoing activities. Inexperience examiners might be tempted to cut short the designated time limit time for a tests so that the school schedule can maintained. Of course, reduced time on a test renders the norms completely invalid and likely lowers the score for must subjects in the group