Exit criterion is used to determine whether a given test activity has been completed or NOT. Exit criteria can be defined for all of the test activities right from planning, specification and execution.
Exit criterion should be part of test plan and decided in the planning stage.
Examples of Exit Criteria:
Verify if All tests planned have been run.
Verify if the level of requirement coverage has been met.
Verify if there are NO Critical or high severity defects that are left outstanding.
Verify if all high risk areas are completely tested.
Verify if software development activities are completed within the projected cost.
Verify if software development activities are completed within the projected timelines.