|Title||How do you know your spreadsheet is right?|
|Authors||Philip L. Bewig|
You know it's true: Spreadsheets have errors like dogs have fleas. It is generally accepted that nine out of every ten spreadsheets suffer some error, and consequences can be severe:
Have a colleague check your work before you publish it.
He should review your documentation, analyze your design, critique your test plan, and test for reasonableness.
Cell-by-cell inspection is tedious, but is the only method of spreadsheet testing known to be effective.
A traffic light tool, such as shown in the figure, can help: