Outpatient Observation Database (OOD) Reporting

Overview

Observation visits are classified as outpatient care and serve a variety of functions, including the reassessment of clinical status and/or continued testing beyond the care provided in an emergency department. Acute care hospitals submit data quarterly to CHIA’s Case Mix databases including information on patient sociodemographics, diagnostic information, treatment and service information, and hospital charges.

Report Materials (May 2026)
Databook (Excel) Technical Appendix (PDF)

Interactive Dashboard

In the February 2025 quarterly update, data on statewide visits and average length of stay by hospital system was added under the statewide utilization section.

The current dashboard relies on interim and final annualized data to present analyses on a quarterly basis from October 2019 through December 2025. The data in the quarterly updates are preliminary.

Updated May 28, 2026

Previous Publication Materials

Recommended Links

Case Mix

Access Massachusetts hospital case mix data, including inpatient discharge, emergency department, and outpatient observation datasets, documentation, and data specification manuals.

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Hospital Inpatient Discharge Database (HIDD) Reporting

Find submission requirements and technical resources for Massachusetts acute care hospitals reporting inpatient discharge data to CHIA's case mix database.

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Emergency Department Database (EDD) Reporting

Find submission requirements, deadlines, and technical resources for reporting emergency department visit data to CHIA's Emergency Department Database.

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