When using benchmarking to test the employee turnover rate, the internal auditor should compare the organization's turnover rate to the published turnover rates of peer organizations. This method provides a relevant standard or point of reference to evaluate the organization's performance relative to similar entities. By using external benchmarks, the auditor can identify whether the turnover rate is above or below industry norms, which helps in assessing the effectiveness of the organization's HR practices.
Reference:
The Institute of Internal Auditors (IIA) Practice Guide: Internal Audit and Organizational Performance IIA Standard 1220 - Due Professional Care