Among the variables contributing to the therapeutic relationship between counselor and client, empathy has received much attention in counseling process research. Most of this research has relied on brief segments as a sampling unit; seldom have these segments been compared with entire counseling sessions. Segments of sessions and entire sessions videotaped by 21 counselors were compared using Carkhuff's measurement of empathy. Thirteen sampling procedures of empathy level were systematically compared with ratings of entire sessions to determine whether the empathy judged from segments was similar to that from entire sessions. Data analyses revealed that, in order to have a reasonable approximation to session-based judgments, a sampling unit should be at least a total of 15 minutes from a 60-minute session, distributed in three segments of five minutes taken in each third of the entire session. A subsequent critical analysis of 48 studies based on a brief segment sampling procedure to measure empathy indicated that only seven studies would have adequate sampling units. The findings suggest that empathy as a broad dimension of counselor relationship qualities may be one aspect of counselor interaction for which sampling units are a difficult substitute for entire sessions. (Author/NRB)