Software inspections have proved to be an effective means to find faults in different software artifacts, and the application of software inspections on requirements specifications is believed to give a high return on investment as problems are caught early. However, despite the existing evidence of positive effects requirements inspections are not a common practice in industry. The reason is believed to be the cost associated with inspections as a technology. This paper presents an evaluation of test-case driven inspections (TCD) - an emerging inspection technique that aims to cut costs associated with traditional requirements inspections. To formally test the efficiency and effectiveness of TCD inspections an experiment was conducted, in a controlled environment, where checklist based inspections was used as a point of reference. The experiment results indicate that TCD inspections perform better when it comes to effectiveness in finding major faults in a requirements specification.