Applying Code Inspection to Spreadsheet Testing

Abstract

:In programming, reliability requires an extensive testing phase. Spreadsheet development, which has about the error rate as program development, also needs to be followed by an extensive testing phase if spreadsheets are to be reliable. In this study, sixty undergraduate MIS students code-inspected a spreadsheet seeded with eight errors. They first inspected the spreadsheet working alone. They then met in twenty groups of three to reinspect the spreadsheet together. Effort was made to prevent hasty inspection.Individual code inspection, consistent with past studies of both spreadsheet and program code inspection, caught only 63 percent of the errors. Group inspection raised this to 83 percent. However, the group phase never found new errors; it merely pooled the errors found during the individual phase by the three members. One group even “lost” an error found during the individual phase. This raises the question of whether a group code inspection phase is really necessary. Other findings were that subjects were overconfident when inspecting alone, that certain types of errors are especially difficult to detect, and that the benefits of the group phase is greatest for these difficult-to-detect types of errors.