of well-mixed, uniform-abundance gas at the same location in the Galaxy. Therefore, with the exception of effects due to post main-sequence evolution, primordial variations in carbon and nitrogen, or contamination from binary companions that have transferred material, the member stars should exhibit very similar elemental abundance patterns. Three of the clusters in our study, M 13, M 15, and M 2, have well-known CN variations that extend to the main-sequence turnoffs (Smith & Briley 2006 for M13; Cohen, Briley, & Stetson 2005 for M15; Smith & Mateo 1990 for M2). However, these abundance variations can be ignored when deriving metallicities from regions of the spectra that do not include CH, CN, or NH features, as is the case with most of our techniques (those that may be affected by the presence of such features are automatically de-selected in the determination of the adopted \[Fe/H\]).

True cluster members should exhibit small radial velocity differences with respect to their parent clusters. Furthermore, it is possible to examine theoretical predictions of temperatures and surface gravities for member stars that lie along the cluster main sequence (MS), red giant branch (RGB), or horizontal branch (HB) in color-magnitude diagrams (CMDs). As part of tests of 