The Merit-based Incentive Payment System: Pearson’s Chi-Square and Categorical Dependent Variable Models Analyzed for Domains—Effective Clinical Care and Efficiency/Cost Reduction

**Background:** Following the 2015 repeal of the Sustainable Growth Rate formula, the US Centers for Medicare & Medicaid Services' formula under which physicians were reimbursed, two payment systems were put in place to incentivize physicians, one of which was the Merit-based Incentive Payment System (MIPS). MIPS emphasizes high-quality care that is accessible, affordable, and supports a healthier population. **Objectives:** This research aims to measure characteristics of MIPS relevant to National Quality Strategy (NQS) domains, quality measure types, and clinical specialties; categorize MIPS with NQS domains and quality measure types by MIPS specialty types; and quantify the relationship between MIPS specialties, measure types, and two NQS domains, Effective Clinical Care (ECC) and Efficiency/Cost Reduction (E/CR), for years 2017 through 2020. **Methodology:** The Pearson’s chi-square test examined distributions of the analyzed categorical variables. The Categorical Dependent Variable Method examined the association between the dependent and independent variables. **Results:** The Pearson’s chi-square test showed statistically significant distributions between ECC and E/CR when analyzed with the types of quality measures. There were more process measures (93.81% vs 89.64% \[*P*=.000]) in 2018 versus 2017. This changed minutely with significantly less process measures (93.75% vs 93.81% \[*P*=.000]) in 2019 versus 2018. Finally, measure types changed minutely but significantly with less process measures (93.81% vs 93.75% \[*P*=.000]) in 2020 versus 2019. The regression model showed that ECC was significantly associated with outcome measures through all analyzed years of this research. **Conclusion:** The above findings show scope for including additional outcome measures, given its importance in MIPS. There is potential to increase the percentage allocation for reporting more outcome measures in quality. This re-allotment infers reporting more outcome measures aligning with priority outcome measures (PROMs). Re-allocating the incentive formula to report more outcome measures aligned with PROMs shows potential to increase reporting of more outcome measures under MIPS.