NCLB waiver requirements have led to development of teacher evaluation systems, in which student growth is a significant component. Recent empirical research has been focusing on metrics of student growth--value-added scores in particular--and their relationship to other metrics. An extensive set of recent teacher-evaluation studies conducted by the Measures of Effective Teaching (MET) project yielded a body of empirical evidence on the correlations among various teacher effectiveness metrics, including scores from several widely-used classroom observation instruments, student surveys, and estimates of teachers' value-added contributions to student test achievement. However, recent studies, including the MET project, consistently show that the non-achievement measures (observations and surveys) have only limited correlation with the academic achievement measures, indicating that they may be measuring facets of teaching other than the teacher's ability to foster higher test scores. This paper will attempt to make the link from knowing what we are measuring in our evaluations to how we would use the information in personnel decisions. This link is viewed in terms of three steps, represented by the questions: (1) What are we measuring with observations and surveys? Can we identify a small set of underlying factors that are being measured? (2) What impact might these other factors have on the overall effectiveness of our education system? (3) How can the factors underlying the evaluation results be used in personnel decisions? The authors present some preliminary results of their analysis that addresses the first question and discuss the approaches to the second and third questions. An appendix contains figures and tables.