Rapid Spreadsheet Reshaping with Excelsior: multiple drastic changes to content and layout are easy when you represent enough structure

Spreadsheets often need changing in ways made tedious and risky by Excel. For example: simultaneously altering many tables' size, orientation, and position; inserting cross-tabulations; moving data between sheets; splitting and merging sheets. A safer, faster restructuring tool is, we claim, Excelsior. The result of a research project into reducing spreadsheet risk, Excelsior is the first ever tool for modularising spreadsheets; i.e. for building them from components which can be independently created, tested, debugged, and updated. It represents spreadsheets in a way that makes these components explicit, separates them from layout, and allows both components and layout to be changed without breaking dependent formulae. Here, we report experiments to test that this does indeed make such changes easier. In one, we automatically generated a cross-tabulation and added it to a spreadsheet. In the other, we generated new versions of a 10,000-cell housing-finance spreadsheet containing many interconnected 2040 tables. We varied table sizes from 510 to 200*2,000; moved tables between sheets; and flipped table orientations. Each change generated a spreadsheet with different structure but identical outputs; each change took just a few minutes.