In this article, the authors aim to present and discuss competing accountability approaches, or models, designed to systematically indicate how a school's students are performing academically. Within the framework of the current federally mandated accountability legislation, increased interest in models measuring school performance has caused educational policymakers to consider several key issues. These issues include whether results from different accountability models yield different inferences about a school's performance, what assumptions underlie each of the models, how different models are implemented, and ultimately which model is best suited for a particular context. The authors address these issues by building a framework for accountability models and then explicitly comparing and contrasting these competing models. In order to accomplish this, the authors first examine two distinct pieces of the larger puzzle. With the first piece, they briefly summarize previous research on school performance. With the second piece, they present building blocks for accountability models. These building blocks include (1) important properties of assessments; (2) test metrics; (3) ways of summarizing student achievement; and (4) options for monitoring achievement growth over time, all of which need to be considered before they are incorporated into an accountability model. The authors conclude with a brief summary and discussion of the salient issues surrounding accountability models. (Contains 4 figures, 2 tables, and 5 notes.)