Search form

Nationwide Emergency Department Sample (NEDS)

Database Name: Nationwide Emergency Department Sample (NEDS)


Data source

Federal-state-industry administrative Healthcare Cost and Utilization Project (HCUP) database managed by the U.S. Agency for Healthcare Research and Quality.  First produced in 2006 and released annually.

Overview of data contents

2010 retrospective dataset approximates a 20% stratified sample of U.S. hospital-based emergency departments (EDs). Contains between 25-30 million unweighted records from over 950 hospitals. Contains information from all payers and all conditions.

Patient ages included

Patients of all ages.

Practice setting

ED encounters and associated inpatient hospitalizations within hospitals participating in the HCUP State Emergency Department Databases (SEDD) and State Inpatient Databases (SID).

Date range available

2006-2010. Cross-sectional only, although cases can be linked to inpatient records if they were hospitalized at the same time as the ED encounter. Data collection ongoing.

Relevant Work

Example publications

Sharp AL, Choi H, Hayward RA. Don't get sick on the weekend: an evaluation of the weekend effect on mortality for patients visiting US EDs. Am J Emerg Med. 2013 May;31(5):835-7.


Cost estimate(s)

$75/year for students. $500/year for all other users.

Contact/website information


Ease of use

The NEDS is among the easier databases to use overall, though sampling methodology may be challenging for researchers inexperienced in health services research. Data are provided on CD; website states that 60-100GB of hard drive space is necessary. Data will need to be converted into Stata, SAS, SPSS or similar format before usage. Some versions of Stata may be unable to handle the entire dataset; selecting subsets of target data may be necessary.

Data analysis

Weighting is required to obtain nationally representative estimates. Weighting requires the use of specific variables provided in the dataset; specific instructions for statistical programming can be found at the HCUP website: Patients cannot be tracked longitudinally. Data variables in NEDS are nearly identical to those in other HCUP databases.


Inexpensive, simple to acquire, clean data.


Lack of longitudinal follow-up withing or across years.