The article discusses a parametric cost analysis to evaluate active soil depressurization (ASD) systems for indoor radon reduction in houses. The analysis determined the relative importance of 14 ASD design variables and 2 operating variables on the installation and operating costs of residential ASD systems in several types of houses. Knowledge of the most important variables would enable EPA's research and development efforts to be more effectively directed at ways to reduce ASD costs and thus to increase utilization of the technology. Parameters offering the greatest potential for reductions in installation costs included three dealing with houses with poor subslab communication: (1) reducing the number of subslab depressurization pipes; (2) eliminating excavation of large subslab pits beneath the suction pipes to improve suction field extension; and (3) improving the effectiveness of premitigation subslab communication diagnostic testing in achieving simpler, less expensive ASD system designs. In addition, determining acceptable conditions for discharging ASD exhaust at grade level would reduce installation costs. Better design guidance for crawl-space submembrane depressurization (SMD) systems could reduce installation costs, if difficult membrane sealing steps and complete coverage of the crawl-space floor by the membrane can be avoided.