Discriminant function analysis has been used to assess morphological distinctiveness of putatively different taxa. We used randomizations of previously published morphological data for 2 subspecies of the coyote, Canis latrans frustror and C. l. thamnos, to quantify a recognized but previously unexamined bias in discriminant-function analyses that use resubstitution classification. This bias results in overestimates of intertaxon distinctiveness and is exacerbated when sample sizes are small. An alternative classification technique, jackknife sampling, is relatively unbiased.