The traditional attest service faces an uncertain future (Elliott [1994]). The advance of the digital economy has created demand for more timely assurance on a broader range of information than provided by the historical financial statement audit (CICA [1999]). A growing body of literature has recommended extending the range of assurance services beyond the financial statement audit (see Bevis [1962]; Wilkinson and Doney [1965]; Imke [1967]; Shenkir and Rakes [1972]; Pratt [1973]; Kinney [1987]; Elliott [1994]; AICPA [1997]; AARF [1997]; Debreceny, Nugent, and Gray [1997J; Fargher and Ganiling [1998]). Similarly, an emerging literature has suggested that the role of the financial statement auditor will evolve to providing assurance on an entity's continuous disclosure systems (CICA [1999]; AICPA [1997] "Elliott Report"; Elliott [1994]). The thrust of the preceding literature is the need to adapt assurance services to a wider range of needs of decision makers in the face of rapid technological innovation.' One such innovation, suggested in this paper, is optimal flexibility in the choice of audit interval that can improve the cost effectiveness of the traditional audit service.