How Coding Accuracy Impacts CMS Hospital Compare Scores

CMS Hospital Compare is a public reporting platform used across the United States to evaluate hospital performance related to quality, patient safety, and outcomes. While not all measures are influenced by coding, several Hospital Compare metrics rely on administrative claims data—making coding and documentation accuracy a critical factor in how performance is calculated and interpreted by Centers for Medicare & Medicaid Services.

Incomplete or inaccurate coding can distort mortality rates, patient safety indicators, and utilization measures, potentially misrepresenting the care delivered. This blog outlines practical coding strategies healthcare organizations can use to support accurate CMS Hospital Compare reporting, strengthen data integrity, and ensure publicly reported results reflect true clinical complexity rather than documentation or coding gaps.

CMS Hospital Compare is a public-facing platform that allows patients, payers, and regulators to compare hospital performance across quality, safety, and outcomes measures. While many Hospital Compare metrics are driven by clinical care processes and patient experience, coding and documentation accuracy play a meaningful role in how certain outcomes are calculated and interpreted.

Inaccurate or incomplete coding can distort mortality, patient safety, and utilization measures—creating a picture of performance that may not fully reflect the care provided. A strategic, quality-focused coding approach helps ensure Hospital Compare data is based on accurate clinical representation rather than documentation or coding gaps.

Here are five proven strategies to help coding teams support accurate CMS Hospital Compare reporting.

1. Understand Which Hospital Compare Measures Are Coding-Sensitive

Not all Hospital Compare measures are influenced by coding, but several outcomes-based metrics rely on administrative claims data, including mortality and patient safety indicators.

• Strategy: Identify which Hospital Compare measures use claims-based methodologies. Focus coding reviews on areas tied to mortality, complications, and utilization rather than process or patient experience measures that fall outside coding’s influence.

2. Strengthen Mortality-Related Coding Accuracy

Mortality measures are risk-adjusted based on diagnoses, procedures, and documented severity. Missed comorbidities, incorrect principal diagnosis selection, or underreported acuity can skew expected mortality calculations.

• Strategy: Perform targeted audits of high-mortality DRGs such as sepsis, respiratory failure, stroke, and cardiac conditions. Validate that principal diagnoses reflect the primary reason for admission and that all clinically supported comorbidities are captured.

3. Reduce PSI Risk Through Accurate POA and Complication Coding

Hospital Compare includes patient safety measures that are sensitive to present-on-admission indicators and complication coding. Inaccurate POA assignment or misclassified complications can negatively impact safety scores.

• Strategy: Reinforce education around POA assignment and complication definitions. Ensure coders differentiate between conditions present at admission, expected outcomes of care, and true hospital-acquired complications.

4. Align Coding and CDI to Support Quality Measures

Coding accuracy is dependent on documentation clarity. Gaps or ambiguity in provider documentation can limit a coder’s ability to accurately reflect severity and clinical complexity.

• Strategy: Encourage collaboration between coding and CDI teams on Hospital Compare–sensitive cases. Joint reviews promote consistent interpretation of clinical indicators, support appropriate queries, and improve documentation quality over time.

5. Monitor Trends Before Data Becomes Public

Hospital Compare data is publicly reported and updated on a set schedule. Waiting until scores are published limits opportunities for proactive correction.

• Strategy: Use internal dashboards, audit findings, and trend analysis to monitor mortality, PSI-related DRGs, and utilization patterns throughout the year. Early identification of coding-driven issues allows for education and adjustment before public reporting cycles.

Final Thoughts

CMS Hospital Compare is highly visible and influential—but it is only as accurate as the data behind it. While coding does not control every measure, coding and documentation integrity are essential to ensuring fair and accurate performance representation. Proactive reviews, targeted education, and collaboration across teams help protect quality scores and reinforce data credibility.

Need support reviewing coding practices tied to Hospital Compare measures? Health Information Associates offers targeted reviews and coding support services designed to help organizations validate their data and approach public reporting with confidence.

FAQ

Since 1992, HIA has been the leading provider of compliance audits, coding support services and clinical documentation audit services for hospitals, ambulatory surgery centers, physician groups and other healthcare entities. HIA offers PRN support as well as total outsource support.

The information contained in this coding advice is valid at the time of posting. Viewers are encouraged to research subsequent official guidance in the areas associated with the topic as they can change rapidly.