According to the sources, PWC took pains to point out that its conclusions about Krung Thai Bank's credit and other practices were necessarily tentative because of the limited sample. (Citing confidentiality issues, PWC declined to speak to Asiaweek about the report.) The auditors recommended a detailed examination of 100 more randomly selected accounts, a suggestion that Mechai and his board approved in July.

CNN: Inside Krung Thai

Eight questions were selected from each decade, and were mixed up in the examination paper, so that students could not easily tell which decade they came from.

BBC: Past science papers stump pupils

"If your return is selected because of a high score under the DIF system, the potential is high that an examination of your return will result in a change to your income tax liability, " says an IRS publication that explains the auditing process.

WSJ: AP Exclusive: Likely tax cheats flock South, West