NCHS Data Online Query System
NCHS DOQS Frequently Asked Questions
Q. What datasets can I access?
A. Currently, NCHS DOQS houses data from the Emergency Department component of the National Hospital Ambulatory Medical Care Survey (NHAMCS-ED), 2005-2007 and 2008. NHAMCS-ED is conducted annually by the National Center for Health Statistics and is a nationally representative sample survey of patient visits to hospital emergency departments. Other datasets will be added in the future.
Q. How do I build a query?
A. Once you've chosen the dataset that you wish to query, select a measure to query from the available options under "Quick Selection." Next, narrow your query by selecting the filters you wish to apply to the data. Depending on the dataset, you can select filters using the available radio buttons, dropdown menus, and check boxes. You may also narrow the search within the filter by selecting subfilters, if available. When you are finished selecting the desired filters, specify how you would like the tables and charts to be displayed. Finally, click on “Submit” to run your query and generate your output. The results of your query can be saved in Excel and XML formats. You can run queries multiple times, with different filters each time.
For more detailed instructions on building queries, see the resources under Getting Started.
Q. How many different filters can I use?
A. That depends on the dataset. Each dataset contains its own unique number and assortment of filters, specific to that particular set of data. For example, the dataset “Emergency Department Visits” offers 13 filters, including Year, Age, Primary Diagnosis, Disposition, and Geographic Region. Each filter contains its own set of filters. “Age” lets you choose six specified age groups (the default setting), individual specified age groups, broader age groups that include older or younger persons, or up to six custom groups with ages from 0 to 100.
Q. Do I have to select from all categories in order to run my query?
A. No. You can select as few or as many as you require.
Q. Do your datasets contain all data available on a subject?
A. Currently, DOQS contains only public-use data files. Researchers seeking additional information may contact the NCHS Research Data Center for information on how to access data not available to the general public.
Q. Does your system require a password login?
A. No. NCHS DOQS is open and available to the public without password restriction.
Q. Is there a fee for using this system?
A. No. There is no fee to use NCHS DOQS.
Q. Who do I contact if I have questions about the data?
A. For questions about data from the National Hospital Ambulatory Medical Care Survey, contact the Ambulatory and Hospital Care Statistics Branch, 301-458-4600, or email NCHSDOQS@cdc.gov. For more information, and to use our Feedback form, see our Contact Us page.
Q. Who do I contact if I have questions about how to conduct my query?
A. For technical questions related to using NCHS DOQS for emergency department data queries, contact the Ambulatory and Hospital Care Statistics Branch, 301-458-4600, or email NCHSDOQS@cdc.gov. For more information, and to use our Feedback form, see our Contact Us page.
A. Persons with disabilities who need assistance in accessing this page should contact email@example.com or call 301-458-4688.
- National Center for Health Statistics
3311 Toledo Rd
Hyattsville, MD 20782-2064
- 1 (800) 232-4636
TTY: 1 (888) 232-6348
- Contact CDC–INFO
Ambulatory and Hospital Care Statistics Branch
National Center for Health Statistics
3311 Toledo Road
Hyattsville, MD 20782-2064
- (301) 458-4600