Figure 6.

Plot of I _obs/σ(I _obs) versus resolution for PDB entry 4epz. (a) At high resolution ice rings are clearly visible, while at low resolution the values are clustered, forming a ‘ladder-like’ scatter plot. (b) The same plot coloured by multiplicity. The higher the multiplicity the larger I _obs/σ(I _obs) is, thus accounting for the behaviour. The value of a measurement is less uncertain the more often it has been made, as shown for example by Watkin & Cooper (2016 ▸). At low resolution, the main influence on these values is their multiplicity. In contrast, at high resolution weaker reflections are influenced by other factors.