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SEDD Overview

Overview of the State Emergency Department Databases (SEDD)

The State Emergency Department Databases (SEDD) are part of the family of databases and software tools developed for the Healthcare Cost and Utilization Project (HCUP). The SEDD capture emergency visits at hospital-owned emergency departments (EDs) that do not result in hospitalization. Information about patients initially seen in the ED and then admitted to the hospital is included in the State Inpatient Databases (SID). The SEDD files include all patients, regardless of payer, providing a unique view of ED care in a State or in a defined market over time.

Developed through a Federal-State-Industry partnership sponsored by the Agency for Healthcare Research and Quality (AHRQ), HCUP data inform decision making at the national, State, and community levels.

This page provides an overview of the SEDD. For more details, see SEDD Database Documentation and the Introduction to the SEDD (PDF file, 446 KB; HTML)


The SEDD capture discharge information on all ED visits in a given State that do not result in an admission. States make their SEDD files available for purchase through the HCUP Central Distributor. See Availability of HCUP Data for a list of State database participation and availability by year.

Forty-two States currently participate in the SEDD:

  • The SEDD contain the ED encounter abstracts in participating States, translated into a uniform format to facilitate multi-State comparisons and analyses.
  • All of the databases include abstracts from hospital-owned ED sites. Composition and completeness of data files may vary from State to State.
  • The SEDD contain a core set of clinical and nonclinical information on all patients, including individuals covered by Medicare, Medicaid, or private insurance, as well as those who are uninsured.
  • In addition to the core set of uniform data elements common to all SEDD, some State data include other elements, such as the patient's race.
Free HCUP Tools & Software are also available to identify preventable hospitalizations, estimate costs, assess quality of care and patient safety, categorize diagnoses and procedures, and identify comorbidities.

Additional information on the SEDD may be found in the Introduction to the SEDD (PDF file, 446 KB; HTML).
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The SEDD contain clinical and resource-use information that is included in a typical discharge abstract, with safeguards to protect the privacy of individual patients, physicians, and hospitals (as required by data sources). The SEDD contain more than 100 clinical and non-clinical variables included in a hospital discharge abstract, such as:

  • All-listed diagnoses and procedures
  • Patient demographics characteristics (e.g., sex, age, and, for some States, race)
  • Expected payment source
  • Total charges
  • Hospital identifiers that permit linkage to hospital inpatient databases, such as the AHRQ-sponsored State Inpatient Databases (SID), and to the American Hospital Association Annual Survey File
Elements included in the SEDD are not always available for all States, including the hospital county identifiers or HCUP's Revisit Variables. Please see the Availability of Data Elements by Year.
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The SEDD are calendar year files based on discharge date for all data years except 2015. Because of the transition to ICD-10-CM/PCS on October 1, 2015, the 2015 SEDD are split into two parts. Nine months of the 2015 data with ICD-9-CM codes (discharges from Jan 1, 2015 - September 30, 2015) are in one set of files labeled Q1Q3. Three months of 2015 data with ICD-10-CM/PCS codes (discharges from October 1, 2015 - December 31, 2015) are in a separate set of files labeled Q4. More information about the changes to the HCUP databases for ICD-10-CM/PCS and use of data across the two coding system may be found on the HCUP-US website under ICD-10-CM/PCS Resources.

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The SEDD combined with SID discharges that originate in the ED are well suited for research that requires complete enumeration of hospital-owned EDs within market areas or States. The SEDD promote comparative studies of healthcare services and support healthcare policy research on a variety of topics, including:

  • Injury surveillance
  • Access to healthcare in a changing healthcare marketplace
  • Trends and correlations between ED use and environmental events
  • Emerging infections
  • Occurrence of nonfatal, preventable illness
  • Community assessment and planning
The SEDD are used in a variety of publications:

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SEDD releases beginning in data year 1999 are available for purchase through the HCUP Central Distributor. Costs vary by State and data year.

All HCUP data users, including data purchasers and collaborators, must complete the online HCUP Data Use Agreement Training Tool, and must read and sign the Data Use Agreement for State Databases (PDF file, 251 KB; HTML).

The SEDD are available for purchase online through the HCUP Central Distributor.

Questions regarding purchasing databases can be directed to the HCUP Central Distributor:

Telephone: (866) 290-4287 (toll free)

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The SEDD data set comes in ASCII format and can be run on desktop computers with a DVD drive. To load and analyze the SEDD, you will need the following:

  • A DVD drive
  • A hard drive with one to four gigabytes of space available, depending on the SID being used
  • SAS®, SPSS®, or similar analysis software
The data set comes with full documentation. SEDD documentation and tools, including programs for loading the ASCII file into SAS or SPSS, are also available on the SEDD Database Documentation page.

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Internet Citation: HCUP Databases. Healthcare Cost and Utilization Project (HCUP). September 2021. Agency for Healthcare Research and Quality, Rockville, MD.
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Last modified 9/15/21