MarketWatch – By Jeremy Olshan: “Microsoft Excel makes it easy for anyone to do the kind of number crunching once reserved for accountants and statisticians. But the world’s best-selling spreadsheet software has also contributed to the proliferation of bad math. Close to 90% of spreadsheet documents contain errors, a 2008 analysis of multiple studies suggests. “Spreadsheets, even after careful development, contain errors in 1% or more of all formula cells,” writes Ray Panko, a professor of IT management at the University of Hawaii and an authority on bad spreadsheet practices. “In large spreadsheets with thousands of formulas, there will be dozens of undetected errors. Given that Microsoft says there are close to 1 billion Office users worldwide, “errors in spreadsheets are pandemic,” Panko says.”