Presidential agenda success is usually accounted for through measures of interbranch cooperation, such as bill approval rates, participation rates, and roll-call data of support from presidential initiatives. These measures do not provide an accurate picture of presidential agenda success because they cannot capture the ability of presidents or Congress to shape the substance of legislation. To overcome this limitation, this paper proposes a combination of two measures of influence on legislative outcomes: the Legislative Input Score for partisan involvement in lawmaking, and the Barrett and Eshbaugh-Soha Scale for legislative substance. To illustrate the potential of these measures, it puts them to work in analyzing the ability of presidents to control the substance of their proposed legislation in Argentina between 1999 and 2007. Preliminary results show that when agenda success is measured with these scores, presidents can consistently shape legislative substance regardless of popularity, coalition size, and honeymoon periods.