This paper aims to identify and compare key factors influencing US States' or an OECD country's decision to employ student test scores or test score value-added (VAM) in evaluating teacher effectiveness. Analysis using multiple linear probability model and logistic regression frameworks indicates that the use of VAM/student test scores was associated with lower NAEP and PISA test scores, and with higher poverty and lower GDP in states and other OECD countries, respectively. These findings suggest that the elevation of standardized comparative test-score metrics pressure relatively lower-performing governing bodies to emphasize accountability for this particular set of educational outcomes.