Pharmacy and Therapeutics (P&T) Committees manage programs that provide patients with effective, safe, and financially sound medication treatments. Despite their importance, little research exists into what committee characteristics lead to adoption of its decisions by prescribers. Considered as "teams", research from the management literature and a qualitative study identified a theoretical model of P&T Committee performance that includes five concepts and a set of four outcome measures. The study aims were to: (1) Describe the variance in P&T Committee functioning and performance in the United States, (2) Quantify drivers of performance within the P&T Committee Performance model and (3) Quantify the relationships between concepts in the P&T Committee model and the effects of these relationships on P&T Committee performance. An on-line and mail cross-sectional survey was sent to 321 Pharmacy Directors, Hospital Administrators/Medical Staff Directors and P&T Committee Chairs at non-university non-specialty hospitals with an ASHP residency. Previously validated measures were used for two concepts, and newly created measures for three concepts. Four dependent variables were used: adoption of formulary medications, medication restrictions, Community-Acquired Pneumonia (CAP) treatment and Deep Vein Thrombosis (DVT) risk assessment protocols. Multivariate regression and path analysis were used with the dependent variables, with five primary variables of interest and five control variables. The response rate was 17.76%. P&T Committee developed processes are successful in leading prescribers to adopting formulary medication decisions (96.02 ± 3.94%), with no differences based on hospital characteristics. They have not been as successful in developing processes for adoption of decisions on medication restrictions (77.02 ± 28.81%) and protocols (63.02 ± 32.76%, 73.02 ± 29.96%). Engaged team members were important in the adoption of all four studied P&T Committee decisions. Influential physicians and implementation activities varied in their importance depending on the decision being made. The presence of influential physicians on the P&T Committee appeared to facilitate both implementation activities and engagement of team members. Influences outside of the committee were insignificant as predictors of decision adoption, possibly an indicator of successful efforts mitigating their influence. This research begins to address previous research gaps about factors affecting adoption of P&T Committee decisions.