The goal was to analyze how organizations that provide extensive external help enhance primary care fare in relation to the amount of money they have already invested in the field. A mixed-methods analysis of 7 EvidenceNOW awardees (henceforth, Cooperatives) and their recruited practices (n = 1,720) was used. Prior to EvidenceNOW, did cooperatives have a strong history of providing widespread quality improvement (QI) to primary care practices (high, medium, or low). Implementation of external support (as measured by facilitation dose), effectiveness in enhancing clinical quality (as measured by practices’ performance on Aspirin, Blood Pressure, Cholesterol, and Smoking [ABCS]), and practice capacity (as measured by Adaptive Reserve [AR] score and Change Process Capacity Questionnaire CPCQ]) were the dependent variables. Multivariate linear regressions and a qualitative inductive strategy were used to analyze the data. EvidenceNOW found that cooperatives with greater prior experience and investment in large-scale QI recruited more geographically dispersed and diverse practices with lower baseline ABCS performance (differences ranging from 2.8% for blood pressure to 41.5% for smoking), provided more facilitation (mean=+20.3 hours, P=.04), and improved both QI capacity (CPCQ: +2.04, P<.001) and smoking performance (+6.43%, P=.003) than those with less prior experience and investment Better recruitment, facilitation delivery, and outcomes could be attributed to the fact that these Cooperatives already had preexisting networks of facilitators in place before the launch of EvidenceNOW and to lead with experience in supporting this workforce. Consistent delivery of facilitation support is associated with greater improvement in practice capacity and some clinical outcomes, suggesting that long-term investments in establishing regional organizations with the infrastructure and experience to support primary care practices in QI are worthwhile.