  A new generation of complete experiments in pseudoscalar meson
photo-production is being pursued at several laboratories. While new data are
emerging, there is some confusion regarding definitions of asymmetries and the
conventions used in partial wave analyses (PWA). We present expressions for
constructing asymmetries as coordinate-system independent ratios of cross
sections, along with the names used for these ratios by different PWA groups.
(This update reflects a recent change in the definition of an asymmetry as used
by one group.)
