On the other hand, most of the ‘Not useful’ comments are either false positives (e.g., when a reviewer incorrectly indicates a problem in the code, perhaps due to lack of expertise) or don’t fall into a predefined category, which we therefore label as ‘Other’. Although, most of the review comments (≈ 73%) fell into one of the categories from Mantyla et al.’s study, we identified four additional categories based on recurring labels interviewees gave to comments in the ‘Other’ category. The new categories were: 1) questions from reviewers, 2) praise for the implementation, 3) suggestions for alternate output or error messages, and 4) discussions on design or new features. The interviewees did not consider comments from the first two categories useful, while in most of the cases they considered the last two categories as useful comments.