Flow diagram of the derivation of indication variables for colonoscopy. *Up to three coded reasons were recorded from each data source during the chart audit. †One indication variable was derived for each data source. ‡This is a single indication assigned to each test combining all coded data collected on each test during chart audit using the computer algorithm shown in Figure 1. It combined data from referral note, progress note and procedure report. §‘N’ is the number of patients. The numbers in parentheses are the tests received by the N patients. ¶A test was selected for review if more than one indication could be assigned or was unknown in all data sources, or relevant free-text data. #Tests on these patients were not selected for review and/or adjudication (see text).