Metrics for comparison of crystallographic maps

Rank scaling of Fourier syntheses leads to new tools for the comparison of crystallographic contour maps. The new metrics are in better agreement with a visual map analysis than the conventional map correlation coefficient.

To free or not to free?

The maximum-likelihood target used for atomic model refinement requires knowledge of statistical parameters. A new method is proposed to estimate them without referring to the test data set thus making refinement more robust.