Modeling Spreadsheet Audit: A Rigorous Approach to Automatic Visualization

Computations in spreadsheets are hard to grasp and consequently many errors remain unnoticed. The problem with the hidden errors lies in the invisibility of the structure of calculations. As a result, auditing and visualization tools are required to make spreadsheets easier to comprehend and to make errors easier to detect. This paper presents a theoretical model of spreadsheets and a technique to describe spreadsheet auditing tools. These are then employed to describe and compare various tools. Moreover, two new visualization mechanisms are introduced.The spreadsheet model reflects not only current spreadsheet systems but also the way people actually use spreadsheets. Theoretically, it is impossible to check the correctness of a spreadsheet without a formal definition of its computations, but our hope is to find visualizations that point out parts of spreadsheets that contain anomalies, i.e. potential locations of errors. The model helps us to understand how such anomalies can be defined.