All impact evaluations depend on quantitative data that typically come from surveys, direct observations of children or service providers, and administrative data like scores from exams. To detect impacts of the interventions under evaluation, we need data that will appropriately measure changes in the outcomes we want the intervention to affect. How do we know we are using the right data and analyzing it appropriately? Enter psychometrics, which is the branch of psychology focused on the design, administration, and interpretation of quantitative assessments. Psychometric evaluations can tell you if you are using the right tools for your measurement goals.