Whereas findings from recent research highlight the importance of teacher quality in improving students' academic performances and experiences of schooling, substantive and methodological issues surrounding the conceptualisation and evaluation of "teacher quality" are not well understood. Such deficiencies are particularly evident in claims for "findings" derived from econometric research--especially from those studies that merely employ conceptualisations and proxy "measures" of "quality" in terms of teachers' qualifications, experience, and students' academic outcomes. Moreover, the econometric models fitted to the available, mostly aggregated data, typically fail to conceptualise and "measure" "teacher quality" in terms of what teachers should "know" (subject-matter knowledge) and "be able to do" (pedagogical skill). Nor do such models account for the measurement, distributional and structural properties of the data for response and explanatory variables--failings that all too frequently yield misleading interpretations of findings for both policy and practice. After brief introductory comments related to current contexts, the paper focuses on two approaches towards the resolution current deficiencies--both of which have important implications for conceptualising and evaluating "teacher quality": (1) capacity building in teacher professionalism grounded in evidence-based preservice teacher education content and subsequent in-service professional development and (2) the specification and evaluation of teaching standards. The paper concludes by arguing that, since the most valuable resource available to any school are its teachers, there is a crucial need for both a substantive and methodological refocus of the prevailing economic "teacher-quality/student-performance/merit-pay" research and policy agenda to one that focuses on the need for capacity building in teacher professionalism (and its evaluation) in terms of "teaching standards" related to what teachers should "know" and be able to do. (Contains 1 figure.)