Outpatient Observation Database (OOD) Reporting

Massachusetts Outpatient Observation Database (OOD) Quarterly Update

(Published February 27, 2025)

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.

In January 2022, CHIA published the Massachusetts Acute Care Hospital Outpatient Observation Data (FFY 2016-2019) report. This report provided information and analyses of hospital outpatient observation utilization patterns in the period leading up to the COVID-19 pandemic and presented measures of observation utilization overall and by hospital, patient, and visit characteristics. 

In the February 2025 quarterly update, data on statewide visits and average length of stay by hospital system have been added under the statewide utilization section. This dashboard relies on interim and final annualized data to present analyses on a quarterly basis from October 2019 through September 2024. The data in the quarterly updates are preliminary. 

Massachusetts Acute Care Hospital Quarterly Outpatient Observation Department Update
(Data through September 2024)

Updated February 27, 2025

Massachusetts Acute Care Outpatient Observation Database Report (October 1, 2015 to September 30, 2019)

(Published January 2022)

This report provides insight into observation department visits in all acute care hospitals in Massachusetts over a four-year period, from FFY 2016 to FFY 2019 (October 1, 2015 to September 30, 2019). This report presents key measures of observation department utilization overall and by hospital, patient demographic, and visit characteristics and is also accompanied by a databook and technical appendix.

This is the first annual statewide report on observation department utilization and part of a new reporting series providing analyses of patterns and trends of acute care hospital services from CHIA’s Case Mix database. In addition to this report, CHIA has published parallel reports on inpatient visits in Massachusetts in December 2020 and emergency department visits in September 2021. In the future, CHIA will produce data updates on a regular basis for all three settings of care to provide timely access to key analyses from these data as they are submitted and processed by the agency.

For further information about Case Mix, including information about data governance, data submissions, data enhancements, and use cases, please see CHIA's Overview of the Massachusetts Acute Hospital Case Mix Database (December 2019).

Key Findings:    

• In FFY 2019, there were 330,324 total observation visits among Massachusetts acute care hospitals: two-thirds of those observation visits (216,037) were observation only and one-third (114,287) resulted in an inpatient admission. 
  
  
• Although the number of observation visits has remained relatively stable over the past four years, the proportion of visits associated with behavioral health increased by 20.2%.
  
  
• Over half (51.2%) of all observation visits were among non-elderly adults (aged 18-64); elderly adults (65 and older) represented another 40.0% of visits, and children represented 8.8% of visits. 
  
  
• The most common expected primary payer type for observation visits was Medicare (42.4%), followed by commercial insurance (27.6%) and Medicaid (22.7%).