The shifting emphasis on performance evaluation and accountability in the context of lending and/or foreign-aid arrangements sponsored by international organizations (IOs) has brought to the fore the question of local ownership of reforms. While the concept of ownership has featured highly in recent academic and policy debates over the effects of IO conditionality, it still remains elusive, ill-identified, and under-specified. In this paper, we focus on International Monetary Fund (IMF) programs and define local ownership with respect to the counterfactual level of de jure structural reforms that would be achieved in the absence of IMF conditionality. We then use the synthetic control method (SCM) to identify continuous levels of ownership as a function of a treatment effect on treated compliers (TETC) and operationalize the concept of ownership over external- and financial-sector conditionality across a restricted sample of uninterrupted IMF arrangements (1980-2014). Furthermore, we probe the criterion and construct validity of our measure with respect to known determinants, proxies, and outcomes of ownership. We argue that ours is a reliable, replicable, valid, robust, and systematic measure of ownership that can help better identify and estimate the indirect relationship between program design and policy implementation.