Purpose - The purpose of this research is to develop an alternative method of measuring out-patient satisfaction where satisfaction is the central construct. The Gap Model operationalized by SERVQUAL is widely used to measure service quality. However, the SERVQUAL instrument only measures expectations (resulting from the pre-process segment of the service experience) and perceptions (resulting from the post-process segment). All three segments should be measured. The lack of proper segmentation and methodological criticisms in the literature motivated this study. Design/methodology/approach - A partial least squares (PLS) approach, a form of structural equation modeling, is used to develop a framework to evaluate patient satisfaction in three service process segments: pre-process, process, and post-process service experiences. Findings - Results indicate that each process stage mediates subsequent stages, that the process segment is the most important to the patient and that the antecedents have differing impacts on patient satisfaction depending where in the process the antecedent is evaluated. Research limitations/implications - Only one out-patient surgery center was evaluated. Patient satisfaction criteria specific to hospital selection are not included in this study. Practical implications - Results indicate what is important to patients in each service process segment that focus where ambulatory surgery centers should allocate resources. Originality/value - This study is the first to evaluate patient satisfaction with all three process segments.