I study the optimal audit mechanism when the principal cannot commit to an audit strategy. Invoking a relevation principle, the agent reports her type to a mediator whi assigns contracts and recommends the principla whether to audit. For each reported type the mediator randomizes over a base-contract and the audit contract, accompanied by a recommendation to audit. For large penalties the optimal mechanism uses strictly more contracts than types and cannot be implemented via offering a menu of contracts. The analysis provides a proper benchmark for studying auditing under limited commitment and sheds new light on the usefulness of mediation in contracting and on the design of optimal mechanisms.
auditing limited commitment mediation contract theory