In four experiments, the utility of a spreadsheet debugging tool was assessed as spreadsheet users interacted with experimental spreadsheets. Experiments 1 and 2 showed that although subjective reactions to the tools were favorable, the performance advantage offered by them was not statistically significant. Experiment 3 assessed the applicability of these tools' with respect to understanding a spreadsheet's structure and data flow. Again, although no performance advantage was shown with the use of the tools, subjective reactions to them were still favorable. Experiment 4 evaluated a more sophisticated version of the tool. The time needed to debug spreadsheets with this tool was shown to be significantly faster than the control condition. Subjective reactions continued to be very positive. Given the interactive nature of working with spreadsheets, the potential utility offered by these interactive tools will hopefully attract the attention of software developers for incorporation into future spreadsheet packages.