Many of the erroneous reports had missing information that may boost a score, such as missing a revolving account in good standing, or miscellaneous incorrect information such as an incorrect birthday.
The foundation of fraud detection is what professionals call "information matching"--reconciling all the information supplied by the taxpayer (including Social Security numbers) with the information on W-2s and 1099 (miscellaneous income) forms, not to mention investment income and bank transactions.