"Statutory inspectors general (IGs) are intended to be independent, nonpartisan officials who prevent and detect waste, fraud, abuse, and mismanagement within federal departments and agencies. To execute their missions, IGs lead offices of inspector general (OIGs) that conduct audits, investigations, and other evaluations of agency programs and operations and produce recommendations to improve them. Statutory IGs exist in more than 70 federal entities, including departments, agencies, boards, commissions, and government-sponsored enterprises."
CRS Report for Congress, R45450
Congressional Research Service: https://crsreports.congress.gov/