Refactoring meets spreadsheet formulas

The number of end-users who write spreadsheet programs is at least an order of magnitude larger than the number of trained programmers who write professional software. We studied a corpus of 3691 spreadsheets and we found that their formulas are riddled with the same smells that plague professional software: hardcoded constants, duplicated expressions, unnecessary complex- ity, and unsanitized input. These make spreadsheets difficult to read and expensive to maintain. Like refactoring of object-oriented code, refactoring of spreadsheet formulas can be transformative. In this paper we present seven refactorings for spreadsheet formulas imple- mented in RefBook, a plugin for Microsoft Excel. To evaluate the usefulness of RefBook, we employed three kinds of empirical methods. First, we per- formed a Retrospective Case Study on the EUSES Spreadsheet Corpus with 3691 spreadsheets to determine how often we could apply the refactorings supported by RefBook. Second, we conducted a User Survey with 28 Excel users to find out whether they preferred the refactored formulas. Third, we conducted a Controlled Experiment with the same 28 participants to measure their productivity when doing manual refactorings. The results show: (i) the refactorings are widely applicable, (ii) users prefer the refactored formulas, and (iii) RefBook is faster and safer than manual refactoring. On average RefBook is able to apply the refactorings in less than half the time that users performed the refactorings manually. 92.54% of users introduced errors or new smells into the spreadsheet or where unable to complete the task.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Computer Science

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2012

Author dc:creator

• Badame, Sandro

Contributors dc:contributor

• Dig, Daniel

• refactoring
• end-user
• spreadsheets
• Microsoft Excel
• code smells

Statement dc:rights

• Copyright 2012 Sandro Badame

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/31155

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/31155