Auditors are doing a far better job of detecting corporate fraud since the 2002 Sarbanes-Oxley Act, while whistle-blowing by employees has declined, a new academic study concludes.

The U.S. law, adopted amid corporate accounting scandals at firms such as Enron Corp., spurred a four-fold increase in auditors uncovering fraud, according to the report. The study of 230 big corporate frauds between 1996 and 2004 found auditors detected nearly 17% of cases after Enron, up from 9.6% in the pre-Enron period.

Among other things, the 2002 law requires an annual assessment of corporate internal financial-reporting controls, and researchers say the yearly effort may help auditors detect fraudulent activity at client firms.

[1] Morningstar: Study: Auditors Now More Likely To Spot Corporate Fraud