In 2012 Michigan implemented Great Start to Quality, a voluntary quality rating and improvement system (QRIS) that uses a multidimensional assessment system to rate the quality of early childhood education programs. Regional Educational Laboratory Midwest examined how changes to Great Start to Quality's rating calculation approach that were announced in 2013 affected program quality ratings. Under the revised approach approximately a third of programs had a higher simulated QRIS rating, although the underlying data and measures of program quality were unchanged. The simpler total score approach yielded simulated QRIS ratings that were nearly identical to those under the revised approach. Minor changes in the calculation approach can yield substantial changes to ratings for individual programs and to the distribution of ratings across the state. When changing the calculation approach, QRIS administrators must consider the cost implications as well as the tradeoffs between having a simple, transparent approach and the benefits of including minimum required scores for different aspects of quality. [This report was produced in collaboration with the REL Midwest Early Childhood Education Research Alliance. For the full report, see ED555393.]