This report deals with the analysis of data used by tax officers to support their claim of tax fraud at a pizzeria. The possibilities of embezzlement under study are overreporting of take-away sales and underreporting of cash payments. Several modelling approaches are explored, ranging from simple well-known methods to presumably more precise tools. More specifically, we contrast common methods based on normal assumptions and models based on Gamma-assumptions. For the latter, both maximum likelihood and Bayesian approaches are covered. Several criteria for the choice of method in practice are discussed, among them, how easy the method is to understand, justify and communicate to the parties. Some dilemmas present itself: the choice of statistical method, its role in building the evidence, the choice of risk factor, the application of legal principles like “clear and convincing evidence” and “beyond reasonable doubt”. The insights gained may be useful for both tax officers and defenders of the taxpayer, as well as for expert witnesses.

中文翻译：

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样本统计数据作为令人信服的证据：税务欺诈案†

本报告涉及对税务人员用于支持他们在比萨饼店进行税务欺诈的索赔的数据的分析。所研究的贪污的可能性是多报外卖销售和少报现金支付。探索了几种建模方法，从简单的众所周知的方法到可能更精确的工具。更具体地说，我们对比了基于正态假设的常用方法和基于 Gamma 假设的模型。对于后者，涵盖了最大似然和贝叶斯方法。讨论了在实践中选择方法的几个标准，其中包括该方法的理解、证明和与各方沟通的容易程度。存在一些困境：统计方法的选择，它在建立证据中的作用，风险因素的选择，“证据确凿”、“排除合理怀疑”等法律原则的适用。所获得的见解可能对税务官员和纳税人的辩护人以及专家证人都有用。