Excerpt from an interesting article posted on the Economix Blog of the NY Times:
Given that the likelihood of being caught is relatively low, says Daniel N. Shaviro, a tax professor at New York University School of Law, most people comply with tax laws because of a "sense of good will, the sense that others are complying and the fairness of the system." The perception of the likelihood of being prosecuted for tax fraud may also be higher than the actual likelihood of being prosecuted, Mr. Shaviro says -- perhaps because the I.R.S. regularly goes after high-profile defendants like Leona Helmsley, who is said to have once proclaimed that "only the little people pay taxes."
Continue reading How Common Is Tax Evasion?

