Global radiation damage to 19 thaumatin crystals has been measured using dose rates from 3 to 680 kGy s -1. At room temperature damage per unit dose appears to be roughly independent of dose rate, suggesting that the timescales for important damage processes are less than ∼1 s. However, at T = 260 K approximately half of the global damage manifested at dose rates of 10 kGy s -1 can be outrun by collecting data at 680 kGy s -1. Appreciable sample-to-sample variability in global radiation sensitivity at fixed dose rate is observed. This variability cannot be accounted for by errors in dose calculation, crystal slippage or the size of the data sets in the assay. © 2012 International Union of Crystallography.