本文延伸Ho and Wang (2013) 所建構的資訊不對稱與審查承諾模型，將政府課稅與逃漏稅行為納入分析架構，探討政府能否事先承諾其稽查政策對納稅人行為與均衡結果之影響。在模型中，借款人於信用市場面臨資訊不對稱問題，而政府於課稅階段亦無法直接觀察納稅人的真實所得，必須透過付出審查成本確認其申報內容，且當高產出者申報其為低產出時，可負擔較少的繳稅金額，因此高所得者具有逃漏稅誘因。本文採用重疊世代模型，並結合賽局理論與混合策略均衡分析，比較政府能夠事先承諾審查機率與無法事先承諾審查機率兩種制度安排下的均衡結果。
研究結果顯示，當政府能夠事先承諾其審查政策時，存在較低的課稅金額與審查機率。相反地，當政府無法事先承諾其審查政策時，由於納稅人預期政府可能因審查成本而降低事後稽查強度，將提高逃漏稅誘因，使政府與納稅人之間形成混合策略均衡。本文進一步證明，相較於事先承諾稽查政策的情況，政府缺乏承諾能力時，均衡下將出現較高的所得稅額與較高的審查機率，進而造成更多資源耗費於資訊驗證活動。整體而言，本文顯示政府政策承諾能力對租稅遵循與資源配置效率具有重要影響。若能建立具可信度的稽查承諾機制，將有助於降低逃漏稅誘因、減少稽查資源浪費，並提升整體經濟效率。

This study extends the asymmetric information and auditing commitment framework developed by Ho and Wang (2013) by incorporating government taxation and tax evasion into the model. The objective is to examine how the government's ability to commit ex ante to an audit policy affects taxpayers' behavior and equilibrium outcomes. In the model, borrowers face asymmetric information in the credit market, while the government cannot directly observe taxpayers' true income during the taxation stage and must incur auditing costs to verify reported income. Since high-income taxpayers can reduce their tax burden by misreporting themselves as low-income taxpayers, they have incentives to engage in tax evasion. An overlapping generations framework combined with game theory and mixed-strategy equilibrium analysis is employed to compare outcomes under two institutional settings: one in which the government can commit to an audit probability in advance and another in which such commitment is not feasible.
The results indicate that when the government can credibly commit to its audit policy, a lower equilibrium tax burden and a lower audit probability can be achieved. In contrast, when the government lacks commitment ability, taxpayers anticipate that the government may reduce auditing efforts ex post because of auditing costs, thereby increasing incentives for tax evasion. Under this setting, taxpayers and the government interact strategically, and a mixed-strategy equilibrium emerges. The analysis further demonstrates that, relative to the commitment regime, the no-commitment regime results in a higher equilibrium tax payment and a higher audit probability, leading to greater resource expenditure on verification activities. Overall, the findings highlight the importance of policy commitment in improving tax compliance and resource allocation efficiency. Establishing a credible audit commitment mechanism can reduce incentives for tax evasion, lower auditing-related resource waste, and enhance overall economic efficiency.

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