A check sheet is a simple form used to collect quality data in real time at the location being observed. It is one of the basic seven tools of quality used for gathering contemporaneous or historical data without analysis. To design an effective check sheet, identify the quality measurements needed, create an easy-to-use form to record that data, and train collectors to gather information consistently and without bias over time while considering seasonal factors. An example is a bookstore manager using a check sheet to identify why customers browse but don't buy by observing purchasing behavior.