NEDS Database Documentation

The Nationwide Emergency Department Sample (NEDS) is a set of hospital-owned emergency department databases included in the HCUP family. These databases are created by AHRQ through a Federal-State-Industry partnership.

The Nationwide Emergency Department Sample (NEDS) produces national estimates about emergency department (ED) visits across the country. The NEDS describes ED visits, regardless of whether they result in admission. One of the most distinctive features of the NEDS is its large sample size, which allows for analysis across hospital types and the study of relatively uncommon disorders and procedures.

The links below provide detailed documentation for the NEDS, from a high-level Overview to all the detailed specifications, restrictions, and resources necessary for researchers working and publishing with the NEDS.

Description of NEDS Database

NEDS Overview

HCUP Partners in the NEDS

Introduction to the NEDS
- 2018 (PDF file, 825 KB; HTML)
- Prior Years
NEDS Related Reports
- Prior Years
Checklist for Working With the NEDS

Restrictions on Use

HCUP Data Use Agreement Training
Data Use Agreement for the Nationwide Databases (PDF file, 85 KB; HTML)
Requirements for Publishing with HCUP Data

File Specifications and Load Programs

Data Elements

Additional Resources for Data Elements

HCUP Quality Control Procedures (PDF file, 383 KB; HTML)
HCUP Coding Practices (PDF file, 138 KB; HTML)
HCUP Hospital Identifiers (PDF file, 162 KB; HTML)

ICD-10-CM/PCS Data Included in the NEDS Starting With 2015

NEDS Changes Beginning Data Year 2016 (PDF file, 255 KB)
Caution: 2015 NEDS includes ICD-9-CM and ICD-10-CM/PCS
- 2015 NEDS Revised File Structure and New Data Elements (PDF file, 560 KB)
Additional ICD-10-CM/PCS Resources
Tutorial for Loading HCUP Software Tools for ICD-10-CM/PCS

Known Data Issues

2011 (PDF file 1.2 MB)
2006 and 2007

HCUP Tools: Labels and Formats

Clinical Classifications Software (CCS)
Format Programs

DRG Formats Program (TXT file, 1.7 MB) Creates SAS formats to label the values of each DRG and MDC category
HCUP Formats Program (TXT file, 63 KB) Creates SAS formats to label the values of selected categorical data elements in HCUP files
HCUP Diagnosis and Procedure Groups Formats Program (TXT file, 39 KB) Creates SAS formats to label the values of HCUP Diagnosis and Procedure Groups data elements, including Clinical Classifications Software (CCS) data elements
ICD-9-CM Formats Program (TXT file, 910 KB) Creates SAS formats to label the values of ICD-9-CM Diagnoses and Procedures
ICD-10-CM Formats Program (TXT file, 11.8 MB) Creates SAS formats to label the values of ICD-10-CM Diagnoses and Procedures

Obtaining HCUP Data

Purchase HCUP data from the HCUP Central Distributor

Internet Citation: NEDS Database Documentation. Healthcare Cost and Utilization Project (HCUP). November 2020. Agency for Healthcare Research and Quality, Rockville, MD. www.hcup-us.ahrq.gov/db/nation/neds/nedsdbdocumentation.jsp.

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Last modified 11/12/20