  The quality of X-ray powder diffraction data and the number and type of
refinable parameters have been examined with respect to their effect on
quantitative phase analysis (QPA) by the Rietveld method using data collected
from two samples from the QPA round robin [Madsen et al. J. Appl. Cryst.
(2001), 34, 409-26]. From these analyses of these best-case-scenario specimens,
a series of recommendations for minimum standards of data collection and
analysis are proposed. It is hoped that these will aid new QPA-by-Rietveld
users in their analyses.
