The two most common strategies for verification and validation, inspection and testing, are in a controlled experiment evaluated in terms of their fault detection capabilities. These two techniques are in the previous work compared applied to code. In order to compare the efficiency and efess of these techniques on a higher abstraction level than code, this experiment investigates inspection of design documents and testing of the corresponding program, to detect faults originating from the design document. Usagebased reading (UBR) and usage-based testing (UBT) were chosen for inspections and testing, respectively. These techniques provide similar aid to the reviewers as to the testers. The purpose of both fault detection techniques is to focus the inspection and testing from a user's viewpoint. The experiment was conducted with 51 Master’s students in a twofactor blocked design; each student applied each technique once, each application on different versions of the same program...