Prior research has investigated the influence of decision maker characteristics on decision choice. This research examines the effect two personality traits of taxpayers, attitude towards risk and ethical standards, on intentional noncompliance. A taxpayer who is more (less) ethical will have lower (greater) intentional noncompliance, while a taxpayer who is more (less) risk averse will have lower (greater) intentional noncompliance. However, this study also found significant correlation between risk attitudes and ethical standards. This is because tax evasion is not just (...) a gamble which can be explained by merely considering the risk variable. To understand tax evasive behavior better requires incorporation of noneconomic factors in the analysis, such as ethical standards, although risk attitudes may be an important explanatory factor. The current research suggests that individuals with lower ethical standards will have more intentional noncompliance. However, since ethical standards are correlated with attitude toward risk, the Internal Revenue Service (IRS) can partially overcome the influence of ethics by making the tax audit environment more uncertain. Thus, the research results justify the decision of the IRS not to release all its audit parameters because it makes the audit environment less uncertain. (shrink)