We present a study investigating the performance of a system for automatically inferring spreadsheet templates. These templates allow users to safely edit spreadsheets, that is, certain kinds of errors such as range, reference, and type errors can be provably prevented. Since the inference of templates is inherently ambiguous, such a study is required to demonstrate the eectiveness of any such automatic sys- tem. The study results show that the system considered performs significantly better than subjects with intermedi- ate to expert level programming expertise. These results are important because the translation of the huge body of exist- ing spreadsheets into a system based on safety-guaranteeing templates cannot be performed without automatic support. We also carried out post-hoc analyses of the video recordings of the subjects' interactions with the spreadsheets and found that although expert-level subjects needed less time and de- veloped more accurate templates than less experienced sub- jects, they did not inspect fewer cells in the spreadsheet.