I am working through Urton Anderson's fabuolously helpful book "Implementing the International Professional Practices Framework" and ran across a recommended preventative measure for fraud in chapter 9 - Benford Law's Analysis.
This rang a few vague bells - so I Googled the term and found this site that looks worth looking into. It includes a quick tutorial on how to analyze data for patterns to detect unusual or fraudulent transactions. See http://www.ezrstats.com/Benford.htm Is this vendor trustworthy? I don't know. What matters is the technique - and that the IIA thinks enough of it to expressly recommend it in its literature.