The NSD formula and the Oxford pig skin experiments

In a recent paper (Berry et al., 19741) pig skin experiments led to the conclusion that the NSD formula failed to correctly represent iso-effect doses in the range of 6–30 fractions. Unfortunately, the authors did not discuss the statistical significance of their results. In fact, my own analysis of their data shows that precisely the opposite conclusion could be drawn, namely, the NSD formula does represent iso-effect doses calculated from their results within experimental error.