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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 2016, generating a average of 8,000 visits per month.

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


The main EVS website is an informational site with links to multiple downloadable files. It has seen increasing use over time, now averaging over 6000 visitors and over 11,000 visits per month

Chart showing unique visitors to 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 Health22265356
National Library of Medicine154
Illinois Century Network78
State of Alabama, Information Services Division22115
German Federal Administration26
Tennessee State Government23
Department of Homeland Security17
Centers for Disease Control1513
Social Security Administration8
NIH-OD, Office of Research Services14
King County Gov13

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

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)

SAP America Hoffmann LaRoche67



Lockheed MartinIBM741
BIOBASE Biological Databases577
Hoffman LaRoche, Inc238
Johnson & Johnson192
ViaSat, Inc.389174
Logical ImagesGlaxoSmithKline243
Ingenuity Systems217
PSINet, Inc.141157
Lockheed Martin128
Level 3 Communications126

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)



Mayo Clinic1856441
Vanderbilt University286
New Jersey Institute of Technology168
Univerza v Ljubljani151
Massachusetts Institute of Technology113
Longwood Medical and Academic Area (LMA)107
George Mason University78
University of New Mexico Health Sciences Center75
University of Geneva71
Colorado Community College System65
University of Muenster55272
University of California, San Diego118
University of Geneva92
University of Muenster64
University of Berlin - Charite51
Massachusetts Institute of Technology49
University of Pennsylvania Health System49
Roosevelt University38

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)

Fred Hutchinson Cancer Research Center



The National Marrow Donor Program178
Kaiser Foundation Health Plan136
BIOBASE Biological DatabasesSanger Institute96
RTI InternationalThe Fred Hutchinson Cancer Research Center81
M.D. Anderson Cancer CenterDana-Farber Cancer Institute62
The European Bioinformatics Roswell Park Cancer Institute50
Translational Genomics Research InstituteFederal Institute for Drugs and Medical Devices, Germany48
Gustave Roussy Cancer CentreThe European Bioinformatics Institute41
Roswell Park Cancer InstituteThe Jackson Laboratory38

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