The Radiation Advisory Committee of the Science Advisory Board reviewed the Office of Radiation Program's approach to analyzing the effects of substituting short-term tests for long-term tests in determining the concenration of radon gas in homes. The Committee endorsed the long-term test in the lowest lived-in space as the standard against which other test results should be judged; noted that the lower the radon level, the less accuractely informed the homeowner is likely to be by results obtained with currently available test devices; expressed concern about the false positive and negative rates that are likely to result from short-term tests near an assumed action level of 4 pCi/L; and noted that the long-term test, when properly done, provides a more scientifically appropriate basis for mitigation decisions, particularly in the range of radon levels most commonly found in U.S. homes.