The cognitive walkthrough method described by Wharton et al. may be difficult to apply in a large software development company because of social constraints that exist in such companies. Managers, developers, and other team members are pressured for time, tend to lapse into lengthy design discussions, and are sometimes defensive about their user-interface designs. By enforcing four ground rules, explicitly defusing defensiveness, and streamlining the cognitive walkthrough method and data collection procedures, these social constraints can be overcome, and useful, valid data can be obtained. This paper describes a modified cognitive walkthrough process that accomplishes these goals, and has been applied in a large software development company.