Besides the two major internal control classifications, (IT general controls and IT application controls), auditors sometimes refer to internal controls as either preventive or detective controls. Preventive controls such as the segregation of duties, are designed to prevent errors, inaccuracy, or fraud before it occurs. Detective controls, such as control group activities, are intended to uncover the existence of errors, inaccuracies, or fraud that had already occurred. Preventive and Detective controls are of complementary of each other, or they even work together in finding and preventing errors, inaccuracies, and fraud. (Whittington, 2019, pp. 322-323)