Finally, other external monitors may provide inputs into the audit process, with real estate firms frequently employing external appraisers in the fair value measurement process. Auditing standards recognize the role of experts, such as International Standard on Auditing 500: Audit Evidence (International Federation of Accountants, 2010), which states that auditors may accept the findings of a specialist hired by management as appropriate audit evidence. This suggests a substitution role: that is, specialists may provide expertise and insights, which can potentially reduce necessary efforts by the auditor to achieve a particular level of audit risk. Prior research provides evidence consistent with this notion: Muller and Riedl (2002) documents that information asymmetry is lower for property firms employing external (versus internal) appraisers in the real estate industry (see also Cotter and Richardson, 2002). Accordingly, we predict that audit fees are lower for firms employing external monitors as part of the fair value reporting process, reflecting potential substitution of efforts. This leads to our final hypothesis: