3. The ModelIn this section, we describe how we have extended and applied the mode! adopted by Boritz and Broca (1986) to the optimal timing of external audits for private companies.
Boritz and Broca (1986) assume that, in the absence of auditing, an audit unit accrues losses that increase the longer the unit remains unaudited. The expected losses (Lj) in the absence of auditing are described by the loss function: