This study was conducted to examine individual differences with respect to values underlying the assessment of teaching competence in order to enhance the effectiveness and fairness of assessment. Nine classroom teachers who were preparing to be mentors of beginning teachers and five teacher educators indicated the relative importance (expressed values) they attached to the following aspects of teaching: teacher/pupil relationships; preparation and management; curriculum content; classroom interaction; assessment and records; and self-evaluation. They then rated the competence of 50 hypothetical student teachers for whom scores were available. Relative weights (implemented values) applied to the aspects of teaching were computed for each participant by employing a regression model, utilizing scores as predictors and participants' overall ratings as criteria. Results found individual differences with respect to both expressed and implemented values, and several participants exhibited discrepancies between expressed values and implemented values. The latter result may reflect a lack of self-awareness and could adversely affect communication among assessors and between assessor and assessee. (Author/LL)