Prevention Coordinators are the linking agents providing technical assistance between universities and communities in the PROSPER model to support the implementation and sustainability of youth and family programs that have reduced substance abuse in prior research. This study examines the outcomes and trajectory of the frequency of contact of technical assistance (i.e. dosage) with community collaborative prevention coalitions across the three stages of coalition development. After communities were randomized, members of PROSPER coalitions (n=12) provided information about the quality of their operations at five time points across four and one-half years; prevention coordinators reported on the frequency of contact with their community coalitions at 14 intervals across the same period of time. This study only utilizes the intervention communities. Results from correlational models show that levels of dosage relate to the quality of internal coalition processes over time, but that the direction of the relationship changes over time: high frequency of contact early on relates to lower coalition-rated functioning initially. In contrast, early frequency of contact relates to higher levels of coalition functioning at later time points. Furthermore, longitudinal mixed models show that levels of dosage were consistent over time. These results provide empirical support of the importance of a proactive technical assistance model and add further evidence that important distinctions exist among different coalition developmental phases.