Innovative, research-based instructional practices are critical to transforming the conventional undergraduate instructional landscape into a student-centered learning environment. Research on dissemination of innovation indicates that instructors often adapt rather than adopt these practices. These adaptations can lead to the loss of critical elements of the practice, which may affect its effectiveness. Process-oriented, guided-inquiry learning (POGIL) is a research-based instructional practice that has been widely disseminated for the past two decades. However, few studies have investigated practitioners' adaptations of POGIL and the impact of these adaptations on expected outcomes measured during recommended implementations of POGIL. In this study, we explore the impact of the implementation of POGIL in discussion sections of a general chemistry and an organic chemistry course on students' grades, retention, attitude toward chemistry, self-efficacy in chemistry, and attitude toward the learning environment provided in these courses. A quasi-experimental design was implemented and data were collected through valid and reliable surveys. Results indicate little to no impact on most measures, although positive trends favoring POGIL students were observed. Discussion of how this particular adaptation of POGIL could explain these results is presented, along with implications for research and practice. (Contains 5 tables and 4 figures.)