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Museum Universe Data File Q&A

What is the Museum Universe Data File?
The Museum Universe Data File is a list of museums in the United States that is maintained by IMLS.  It is the most comprehensive list of U.S. museums available, and it indicates that there are35,144 museums in the United States, more than double the previous IMLS estimate of 17,500.

Why is the number so much larger than before?
The earlier estimate was based primarily on information IMLS obtained from state museum associations and their membership records. Now, new access to administrative records, especially the Internal Revenue Service 990 non-profit data, has made it possible for IMLS to get a more complete picture of the museum sector in the U.S.

What information about museums was collected and is available?
The information in the newly released file includes basic institutional identifying information such as name, address, city, state, museum type, phone, website, revenue, and various geographic markers. 

What was the methodology?  
The new estimate is based on data drawn mainly from IMLS’s own administrative records (2009 – present) and data from the Internal Revenue Service on nonprofits (from IRS Form 990 and IRS Form 990-N filers, 2009 – present). In addition, IMLS drew information from third party commercial vendors.

How accurate is the Museum Universe Data File?
While the IRS data provide fairly comprehensive information about non-profits in the U.S., there is no similarly comprehensive source for information about public and for-profit museums. Museums governed by state and municipal agencies or museums under the control of public universities may be undercounted.  

Did IMLS use information from the Official Museum Directory?
IMLS did not use the Official Museum Directory as a data source. The Official Museum Directory maintains a license that restricts use of the information it maintains.

How can the Museum Universe Data File be used?
The Museum Universe Data File and the information it contains are open and publicly available for use without restriction. Researchers, media, and the museum-interested public may use the file to learn about museums in the United States. The file also can be used to develop national estimates of the museum universe, to sample museums for further analysis, and to identify museums using a variety of geographic markers.

What is the breakdown by museum type? Where did the type categories come from?
The classification type used for the Museum Universe Data File primarily is based on the National Taxonomy of Exempt Entities (NTEE)classification. This classification system is used by the IRS and the National Center for Charitable Statistics (NCCS) to classify nonprofit organizations. Classification of museum type for each museum was based on information from the data sources used.

How will the data file be maintained?
This database will undergo periodic review and updates. IMLS encourages the museum community to examine the database and to contact the IMLS research staff if there are institutions that should be added or entries that should be deleted. IMLS is accepting comments at