Kyle Rector

Our spreadsheet methodology has criteria for designing, building, and validating spreadsheets to ensure that they work correctly.

See our bibliography of spreadsheet best practice, risk management, errors and testing, and methods for improving spreadsheets.

"Oh My God" my formulas are not working! This article covers most of the reasons for Excel formulas not working. And how to fix them.

This early spreadsheet, a Babylonian clay tablet c.1800 BC, contains several errors. How many errors do your spreadsheets have?

Every study that has looked for errors has found them in considerable numbers. Spreadsheeting's childhood is over.

Connexion is a collection of the most useful and interesting spreadsheet-related articles from the web.

Incorrect use of Excel's NPV function is a common source of spreadsheet errors. We show several pitfalls and ways to avoid them.

Errors in the data, formulas, or manipulation of spreadsheets could be costly, even devastating.