考量國稅局選案查核率與逃漏稅行為之內生關係，本研究應用聯立方程模型探討民國89年至91年度台灣營利事業所得稅之租稅逃漏情形，並分別利用Tobit及Probit模型來分析營利事業租稅逃漏及國稅局選案查核時之各項影響因素。實證結果顯示我國國稅局於選案查核時，對各申報案件之選案查核受到各案件申報行為、案件特性及查核資源等因素所影響。可見國稅局在有限的查核預算及人力下，會有系統性的採用特定之查核法則來進行其選案查核程序。此外，本文亦發現在其他條件不變下，採用會計師稅務簽證、流動性較高及享有租稅減免優惠等申報案件，其所得稅逃漏情形較少；另一方面，課稅所得愈多、負債比率較高、逾期申報及申報時仍須補稅之營利事業，其逃漏情形則較高，可見營利事業之逃漏行為顯著受到其本身之特性所影響。然而，本文並未發現國稅局之選案查核率對各申報案件當年度及以後兩個年度之租稅逃漏有遏阻之作用。

This study uses Taiwan's business income tax returns data from 2000 to 2002 and Tobit and Probit models to simultaneously investigate the determinants of audit selection and business income tax evasion behavior. Our findings indicate that Taiwan's tax authorities employ a systematic audit selection process based on the availability of audit resources and the information reported by the taxpayers to select returns for audit. Firms with CPA-attested tax return, adequate liquidity and tax preference status will more likely behave in compliance with tax laws. Other firm characteristics including levels of taxable income and debt ratio, history of missing filing deadlines, and the tax-payment-due status at filing time have significant positive association with noncompliant tax reporting behavior. However, our results fail to support the notion that higher likelihood of tax audit may serve as a deterrent to corporate tax noncompliance in Taiwan.