Auditing Standard No. 13
The Auditor's Responses to the Risks of Material Misstatement
Appendix A – Definitions
A2. Dual-purpose test – Substantive test of a transaction and a test of a control relevant to that transaction that are performed concurrently, e.g., a substantive test of sales transactions performed concurrently with a test of controls over those transactions.
A3. Period of reliance – The period being covered by the company's financial statements, or the portion of that period, for which the auditor plans to rely on controls in order to modify the nature, timing, and extent of planned substantive procedures.