Emergency Department and Ambulatory Surgery Data
Public Data Set
The California Office of Statewide Health Planning and Development (OSHPD) provides public data sets of inpatient, emergency care, and ambulatory surgery data collected from licensed California hospitals, hospital emergency departments, and licensed freestanding ambulatory surgery clinics in California. Each record within the data sets consists of either one inpatient discharge, or one outpatient encounter, also known as a service visit. Data included on the public data sets includes clinical, payer, and facility information. Beginning in 2013, with the release of 2012 data, the Public Use File has been modified to protect patient confidentiality and minimize the risk of disclosure of confidential patient data while preserving most of the file's clinical information.
Documentation in a pdf format that accompanied the prior versions of the public use file:
2012: Revised Public Use File Information and ordering instructions
2011: 1st half / 2nd half | 2010: 1st half / 2nd half | 2009: 1st half / 2nd half | 2008: 1st half / 2nd half
2007: 1st half / 2nd half | 2006: 1st half / 2nd half | 2005: 1st half / 2nd half
An outpatient encounter record is submitted each time a patient is treated in a licensed emergency department or ambulatory surgery center in California. These facilities report their encounter data via the Medical Information Reporting for California System (MIRCal). The reported data include patient demographic information, such as age, sex, county of residence, and race/ethnicity, diagnostic information, treatment information, disposition, and expected source of payment. County Frequencies for Emergency Department and Ambulatory Surgery outpatient encounters by patient county of residence can be downloaded below:
Ambulatory Surgery Center Encounters, County Frequencies by Patient County of Residence2005 | 2006 | 2007 | 2008 | 2009 | 2010 | 2011 | 2012
Emergency Department Encounters, County Frequencies by Patient County of Residence2005 | 2006 | 2007 | 2008 | 2009 | 2010 | 2011 | 2012
View information for Patient Discharge Data.
Emergency Department (ED) and Ambulatory Surgery (AS) Profile Reports
ED and AS Profile Reports are collected through MIRCal and may be accessed by data type, facility ID# or facility name and report period begin and end dates. Each report consists of a two-page summary which represents the number and percentage of each data element for a given facility.
- Ambulatory Surgery (AS) – Top Ten Procedure Groups – 2012
- A statewide listing of the top ten principal procedure groups, based on Current Procedural Terminology, Fourth Edition (CPT-4). Includes both hospital based ambulatory surgery and freestanding ambulatory surgery centers.
- Emergency Department (ED) Encounters by Facility – 2012
- A listing, by hospital, of the number of ED encounters. Includes both ED encounters and admissions through the ED.
- Emergency Department (ED) – Top Ten Cause of Injury - 2012
- A statewide listing of the top ten principal external cause of injury codes reported by Emergency Departments. This data is only from ED encounters that did not result in a hospital admission.
- Emergency Department (ED) – Top Ten Diagnoses and Diagnoses Groups -
- A statewide listing of the top ten principal diagnosis codes reported by Emergency Departments. Also included is a statewide listing of the principal diagnoses groups (based on ICD-9-CM codebook chapters). This data is only from ED encounters that did not result in a hospital admission.
Attention Data Users: Please exercise caution when interpreting OSHPD data. The use of improper assumptions and analytical methods may result in erroneous or misleading conclusions. Conclusions drawn from OSHPD data are the sole responsibility of the user. Users should be aware that financial and utilization data products are based on a dynamic database that is constantly being updated. As a result, the same data item for a facility may change over time or be different between products.
If you are unable to download ZIP or EXE files, please e-mail the OSHPDWebmaster.
Extracted files can be e-mailed to users at no charge.