The article proposes a simple Bayesian technique for auditing property appraisals to determine whether state accuracy guidelines are met. The proposed technique addresses elicitation of appraisers' prior beliefs, computation of reappraisal sample sizes and reporting of audit results. To facilitate communication of quantitative audit findings to nonstatistician stakeholders, the concept of variance appears nowhere in prior elicitation or reporting. In contrast to classical frequentist techniques, the Bayesian procedure easily integrates expert judgment and responds flexibly to the arrival of new information. In addition, the Bayesian procedure significantly reduces the number of reappraisals required to regulate appraisal systems when they are functioning well. The technique can be applied in other settings where government officials audit their own work and must convince overseers, especially the public, that accuracy requirements are satisfied.Public-sector property appraisers, whose responsibility is to compute annual property valuations for use by tax assessors and attest to their accuracy, are providers of technical expertise and what Walls and Quigley (2001) refer to as socio-technical services. Socio-technical services are those that require specialized communication skills for eliciting statistical information from nonstatisticians and for persuasively explaining quantitative issues to various stakeholders, in this case taxpayers, users of public services financed by property tax revenue and other constituencies in the local or regional political economy. The task of communicating algorithmic detail from the computation of property owners' tax bills and attesting to the effectiveness of quality control measures clearly fits the socio-technical label.The focus of this article is the audit of public-sector property appraisals. Such audits require reappraisal of a relatively small number of properties using costly, in-depth appraisal methods and, thus, determination of an appropriate reappraisal sample size. The goal is to convince state officials and members of the