Nine experienced users of electronic spreadsheets each created three spreadsheets. Although participants were quite confident that their spreadsheets were accurate, 44 percent of the spreadsheets contained user-generated programming errors. With regard to the spreadsheet creation process, we found that experienced spreadsheet users spend a large percentage of their time using the cursor keys, primarily for the purpose of moving the cursor around the spreadsheet. Users did not spend a lot of time planning before launching into spreadsheet creation, nor did they spend much time im a separate, systematic debugging stage. Participants spent 21 percent of their time pausing, presumably reading and/or thinking, prior to the inital keystrokes of spreadsheet creation episodes.

--Authors’ Abstract

Two important findings have resulted from this research. The first is the large percentage of spreadsheets with errors. From the analysis, the errors are largely a result of errors in cell formulas. The second is the lack of time spent by developers in planning spreadsheets. Though none of the spreadsheet exercises are large (the longest average time to develop a spreadsheet is 63 minutes), the overall lack of planning is a surprise.

These findings focus attention on the need for improved user interfaces and support utilities. Debugging assistance would be of particular interest. Specifically, interfaces that permit views of the spreadsheet formulas, values, and cell addresses across a number of cells and across different areas of the sheet might reduce the error rate. Organizing and displaying formulas, values, and cell addresses that are related to or arise from one another could also help.