The evaluation of key internal controls should result in a specific determination of their effectiveness. Contracting managers shall use the checklist questions in appendix BB to test key controls of contracting functions through a combination of document analysis, direct observation, and random sampling. The annual statement of assurance and supporting documents shall include a corrective action plan for deficient answers to checklist questions. The contracting checklist in this appendix is not all-inclusive and each contracting activity should supplement the checklist with area-specific questions (e.g., major systems, etc.). Formal evaluations of key management controls must be conducted at least once every five years (Army Regulation 11-2).