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Markus Clermont, Christian Hanin, & Roland Mittermeir


Amongst the large number of write-and-throw-away-spreadsheets developed for one-time use there is a rather neglected proportion of spreadsheets that are huge, periodically used, and submitted to regular update-cycles like any conventionally evolving valuable legacy application software. However, due to the very nature of spreadsheets, their evolution is particularly tricky and therefore error-prone.

In our strive to develop tools and methodologies to improve spreadsheet quality, we analysed consolidation spreadsheets of an internationally operating company for the errors they contain. The paper presents the results of the field audit, involving 78 spreadsheets with 60,446 non-empty cells. As a by-product, the study performed was also to validate our analysis tools in an industrial context.

The evaluated auditing tool offers the auditor a new view on the formula structure of the spreadsheet by grouping similar formulas into equivalence classes. Our auditing approach defines three similarity criteria between formulae, namely copy, logical and structural equivalence.

To improve the visualization of large spreadsheets, equivalences and data dependencies are displayed in separated windows that are interlinked with the spreadsheet. The auditing approach helps to find irregularities in the geometrical pattern of similar formulas.


The Structure Browser with example data
The Structure Browser with example data

In order to support the auditing process we developed a toolkit that automatically performs the partitioning into equivalence classes.

The toolkit consists of three main parts:

  • A structure browser to show the decomposition of the spreadsheet into equivalence classes.
  • A dependency viewer that displays the data flow graph between these dependencies.
  • The spreadsheet itself giving feedback to the auditor by highlighting the cells that are in the equivalence class that is currently selected in the structure browser.


2002, EuSpRIG

Full article

A spreadsheet auditing tool evaluated in an industrial context