Running Head: SIMPLE CHOICES AMONG ACSMS Simple Choices among Aggregate-Level Conditional Status Metrics: From Median Student Growth Percentiles to Value-Added Models

Aggregate-Level Conditional Status Metrics (ACSMs) describe the status of a group by referencing current performance to expectations given past scores. This paper focuses on seven ACSMs that condition only on past scores, including median Student Growth Percentiles (Betebenner, 2009), aggregated Percentile Ranks of Residuals (Castellano & Ho, 2012) and covariate-adjustment “value-added” models (e.g., McCaffrey et al., 2004). The authors define “simple” choices among these ACSMs (e.g., between meanand median-based aggregation functions, or between fixed and random effects). They evaluate the impact of these choices upon three practical factors: school rankings, robustness across inclusion of prior-year data, and invariance to nonlinear scale transformations. Findings include expressions of practical differences between ACSMs and suggest considerable advantages of mean-based over medianbased metrics.