Publisher Summary This chapter focuses on the free R value and other applications of cross-
validation in crystallography. Powerful methods have been developed to lower the chances …

Analogies between the free R statistic [Brünger (1992). Nature (London), 355, 472–474] and
the statistical methods of cross validation and bootstrap are discussed. Several new …

phenix. model_vs_data is a high-level command-line tool for the computation of
crystallographic model and data statistics, and the evaluation of the fit of the model to data …

In 1990, Brändén and Jones [1] suggested that the process of electron-density map
interpretation involves a degree of subjectivity on the part of the crystallographer. In the …

An online computing server, Online_DPI (where DPI denotes the diffraction precision index),
has been created to calculate theCruickshank DPI'value for a given three-dimensional …

As in all scientific measurements, the parameters that result from a macromolecular structure
determination by X-ray crystallography (eg atomic coordinates and B factors) will have …

This paper reviews the mathematical basis of maximum likelihood. The likelihood function
for macromolecular structures is extended to include prior phase information and …

The most popular estimator of structural similarity is the root-mean-square distance (rmsd)
between equivalent atoms, computed after optimal superposition of the two structures that …

A new translation function T (t) is defined, whose main peak is expected to give directly the
absolute position t= t0 of a known molecular configuration (the isostructural model) of known …

The last five years have seen a large increase in the use of cross validation in the refinement
of macromolecular structures using X-ray data. In this technique a test set of reflections is set …