Data-collection strategies

The optimal strategy for collecting X-ray diffraction data from macromolecu lar crystals is discussed. Two kinds of factors influencing the completenes s of data are considered. The first are geometric, arising from the symmetr y of the reciprocal lattice and from the experimental setup; they affect qu antitatively the completeness of the measured set of reflections. The secon d concern the quality, or information content, of the recorded intensities of these measured reflections.