Response to the Letter to the Editor by Drs. Tschiersch and Haninger

We thank Tschiersch and Haninger (1) for their comments on our analysis of temporal and spatial variation of radon measurements in dwellings in Gansu Province, China (2). Within the case–control study of lung cancer and residential radon, we conducted a sub-study to estimate uncertainties in radon (i.e. ²²²Rn) exposure assessment by placing three pairs of co-located detectors in each of several rooms of 55 dwellings for three consecutive years. Many of the dwellings were underground “cave-type” dwellings, and radon levels were notably high. In addressing uncertainties in radon exposure assessment, Tschiersch and Haninger take issue with our decision not to take any special account of uncertainties arising from the measurement device. Based on a components of variance analysis, our best estimate of the coefficient of variation (CV) was 0.50 (SE 0.02) for the temporal and spatial uncertainties in radon concentration...