Types of controls: preventive, detective, corrective, compensating; general vs application controls

A control is any policy, procedure, practice or technical mechanism that management puts in place to give reasonable assurance that objectives will be met and that risks stay within acceptable limits. Auditors classify controls so they can judge whether the mix is sensible and decide how to test each one. The same control can be described in several ways at once: by its function, its scope and whether it is manual or automated.