The three diagnostic dimensions of the Concerns Based Adoption Model (CBAM) are tools that can evaluate the degree of new program implementation at the classroom level. Implementation success is a function of use/nonuse, appropriate/inappropriate practice, and user concerns about the innovation. These dimensions: Levels of Use (LoU) of the Innovation, Innovation Configurations (IC) and Stages of Concern (SoC) about the Innovation can measure and rank progress for individuals or groups, be combined for a composite ranking, and be used for exploring the relationship between implementation success and change process variables. These procedures were applied to the Principal-Teacher Interaction Study to assess implementation success across nine elementary schools in Colorado, Florida, and California. Study sites varied by principal's approach to facilitation, year of implementation, and innovation being implemented. Throughout the 1980-81 school year, data were collected from bi-weekly phone calls to principals and four on-site visits. Teacher data were collected using the CBAM diagnostic dimensions. Rankings were done during three 3-day meetings by research staff and school district representatives. Results suggest close monitoring feed back and more interventions will improve implementation success. Principal change facilitator style significantly influenced teacher classroom practice. The appendix details the three diagnostic dimensions of the CBAM. (BS)