Outcomes-based funding (OBF) has become an increasingly common tool for states seeking to improve student outcomes, and the inclusion of certificates in OBF policies has been subject to considerable scrutiny. But studying the effects of OBF on certificates is exceptionally challenging. Certificates vary greatly in length, type, and labor market value. Additionally, states vary in how they define and reward certificate completions, and OBF policies change frequently. Finally, available databases do not adequately capture these variations. These factors make it difficult to ascertain whether and how OBF policies have affected certificate attainment and student economic and social mobility. This research brief lays out both the challenges and opportunities inherent in studying the effects of OBF on certificate attainment by: (1) Summarizing what is known about variation in the type, length, and value of certificates; (2) Documenting variation in how states currently define and reward certificates in OBF formulas; (3) Illustrating the limitations of available datasets to capture this variation; and (4) Providing a set of recommendations for how the field can better examine the intended and unintended effects of including certificates in OBF policies. This brief identifies a range of challenges as well as possible solutions to better capture important variations in certificates and how they are recognized in OBF formulas.