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The next several sections analyze available statistics for direct use of EVS resources on EVS servers. This section covers direct use of NCI-hosted EVS terminology browsers and the LexEVS local java API that supports them. Later sections cover the LexEVS distributed (remote), LexEVS caGrid services, the term suggestion site, and ftp download services.

Table of Contents

The EVS browsers and LexEVS APIs at NCI are covered by the AWStats and Wusage applications, recording various statistics including number of unique visitors, visits, number of pages viewed and data volume accessed. These have been collected below to give a window into the use of the EVS services. Appendix 1 lists the usage tracking pages from which these statistics are gathered.

We are now able to identify and exclude most web crawler and similar automated hits, as well as internal use for testing and development purposes. Detailed examination of addresses and patterns of use suggest that the use reported below overwhelmingly represents real users from NCI and other organizations of interest. Analyzed below are figures for unique visitors and number of visits, as well as the volume of data communicated, which for all but ftp sites reflects high volumes of traffic in mostly compact units of terminology concept data.

Statistical Overview

The EVS browsers run off the LexEVS local API, and provide the highest number of direct users of EVS terminology servers. The lowest, but most informative, numbers are for unique visitors and number of visits. The number of unique visitors to the EVS family of browsers has averaged around 4,000 per month in 2015, growing to around 10,000 per month by the end of 2016 generating some 17,000 visits.

Unique visitors to EVS browsers, per month
Chart showing unique visitors to EVS browsers per month





NCI Term Browser (many terminologies, value sets and mappings)


NCI Thesaurus Browser (now one face of NCITerms, counted separately)


NCI Metathesaurus Browser (separate app, searchable from NCITerms)


EVS Term Suggestion site (covered later)


Number of visits to EVS browsers, per month 
Chart showing number of visits to EVS browsers per month

Browser Users

The data below is from January - December 2015. It shows an overall view of which internet domains hit EVS browsers most heavily, and then breaks down each domain by top users. All browsers are put together for this analysis.

Overall Use

The amount of bandwidth used was divided into four (4) major groups: Government .gov users, private .com and .net users, Educational .edu institutions, and Organizations .org. The data was analyzed and bots were discarded to avoid skewing the data.

Data accessed (MB) from EVS browsers by domain











Data accessed (MB) from EVS browsers by domain
Chart showing data access(MB) from EVS browsers by domain

Users from .gov domain

The numbers below show the top government users of the EVS browsers, as measured by the MB of data that were accessed. Agency names have been provided where they are known. The main users are internal to NCI and NIH, which is not surprising, but we have substantial FDA usage as well.

Top .gov EVS browser users: Data accessed (MB)




National Institutes of Health1558216102
National Library of Medicine104198
U.S. Dept. of Health and Human Services91
National Library of Medicine50
Illinois Century Network28State of Minnesota
Department of Homeland Securty21
State of Oregon27
Alabama, Information Services Division12


Top .gov EVS browser users: Data accessed (MB)
chart showing data access by dot gov EVS browser usersImage Modified

Users from .com domain

We combined the .net and .com users into one group as both contained a number of private corporations and individual users from a wide variety of internet service providers (ISPs). Business names have been provided where known. The graph below does not show ISPs as they are not interpretable and dwarf the next largest groups.

Top .com EVS browser users: Data accessed (MB)



PSINet, Inc.280
Hoffmann LaRoche, Inc. 257
Spartanburg Regional Health Services District, Inc.154
IBM Rochester92
Johnson & Johnson85

Top .com EVS browser users: Data accessed (MB)
chart showing data access by dot com EVS browser users

Users from .edu domain

The edu users were widely distributed across many American universities and a small selection of foreign institutions.

Top .edu EVS browser users: Data accessed (MB)



Vanderbilt University 265
Mayo Clinic 166
University of Geneva 101
University of Nebraska Medical Center 40
MD Anderson Cancer Center - University of Texas 37
University of Arizona 28
University of Chicago 27
Mount Sinai School of Medicine 19
Wake Forest University Baptist Medical Center 17
Johns Hopkins Medicine 16

Top .edu EVS browser users: Data accessed (MB)
chart showing data access by dot edu EVS browser users

Users from .org domain

Like the .edu users, the .org users were widely distributed across a variety of organizations.

Top .org EVS browser users: Data accessed (MB)



Children's Oncology Group 92
The Fred Hutchinson Cancer Research Center 79
Roswell Park Cancer Institute 53
Kaiser Foundation Health Plan 40
The National Marrow Donor Program 37
The Jackson Laboratory 33
Mission Hospitals, Inc. 27
OneCleveland 21
The University Of Texas M.D. Anderson Cancer Center 21

Top .org EVS browser users: Data accessed (MB)
chart showing data access by dot org EVS browser users

Usage Patterns of the Three EVS Browsers

The three browsers offered by EVS are

NCITermsNCI Term Browser: Access to all terminologies, value sets and mappings.
NCItNCI Thesaurus Browser: Now just one face of NCITerms, but the most used and counted separately.
NCImNCI Metathesaurus Browser: A separate application, searchable from NCITerms.

broswer usage pie chart

Nearly 75% of all use goes to the NCIt browser, including almost all use from the educational domain and two thirds of government use.  By contrast, half of commercial domain use goes to NCI Terms, while .org use is almost evenly split between all three browsers.

dot com browser usage pie chart  dot edu browser usage pie chart dot gov browser usage pie chart dot org browser usage pie chart