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Syntax and Operability Accuracy of WHOIS Data in gTLDs Presented in Accuracy Reporting System Phase 2 Report

23 December 2015

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ICANN today published the Phase 2 report of the WHOIS Accuracy Reporting System (ARS), which acts as a follow-on to the Phase 1 report published in August 2015. During Phase 2, ICANN measured both the syntax and operability accuracy of WHOIS records in gTLDs as compared to the requirements of the 2009 and 2013 Registrar Accreditation Agreements (RAAs).

Read the Phase 2 Report.

In addition to testing the format and content of a sample of WHOIS records, ICANN developed accuracy tests to answer questions about the operability of WHOIS records:

  • Does an email sent to the email address provided in the WHOIS record bounce back?
  • Does the telephone number provided ring when dialed?
  • Will mail be delivered to the given postal address?

Then using statistical methods, syntax and operability accuracy estimates with a 95 percent confidence interval were provided for the population of domains in gTLDs as a whole, as well as for several subgroups of interest.

The analysis found, for example, that approximately 87 percent of email addresses, 74 percent of telephone numbers and 98 percent of postal addresses were operable. See Table 1 below for more information.

Table 1: Overall gTLD Operability Accuracy by Contact Mode (95 percent confidence interval)



Postal Address

All 3 Accurate

All 3 Contacts (Registrant, Technical, Administrative) Accurate

87.1% ± 0.7%

74.0% ± 0.9%

98.0% ± 0.3%

64.7% ± 0.9%

In terms of syntax accuracy, the Phase 2 report shows similar results to Phase 1. That is, approximately 99 percent of email addresses, 83 percent of telephone numbers and 79 percent of postal addresses were found to meet all the requirements of the 2009 RAA. Table 2 below provides more information.

Table 2: Overall gTLD Syntax Accuracy to 2009 RAA Requirements by Contact Mode (95 percent confidence interval)



Postal Address

All 3 Accurate

All 3 Contacts (Registrant, Technical, Administrative) Accurate

99.1% ± 0.2%

83.3% ± 0.7%

79.4% ± 0.8%

67.2% ± 0.9%

The Phase 2 report contains additional details regarding both syntax and operability accuracy, including important notes on the differences between Phase 1 and Phase 2. The Phase 2 report also discusses the leading types of nonconformances, trends and comparisons of WHOIS accuracy across regions, RAA versions and gTLD types.

Next Steps for Phase 2

ICANN will host a webinar on 12 January 2016 at 16:00 UTC to provide insight into the methodology and findings of the WHOIS ARS Phase 2 report. An announcement with more details on how to participate will be released in the coming weeks.

The results of Phase 2 have been provided to ICANN’s Contractual Compliance team, which will assess the types of errors found and follow up with registrars on potentially inaccurate records. If WHOIS inaccuracy and/or format complaints are created from the WHOIS ARS data, ICANN Contractual Compliance will issue tickets in accordance with the Contractual Compliance Approach and Process.

Next Steps for the WHOIS ARS

In January 2016, ICANN will also begin work on second cycle of Phase 2 of the ARS, which will again measure both syntax and operability of the contact information in WHOIS records. Testing is expected to be complete by April 2016 and a report on Phase 2 Cycle 2 is targeted for June 2016.


ICANN reviews the WHOIS Program every three years as part of its Affirmation of Commitments (AoC). On 8 November 2012, the ICANN board approved a series of improvements to the manner in which ICANN carries out its oversight of the WHOIS Program based on recommendations made by the 2012 WHOIS Review Team. As part of these improvements, ICANN committed to proactively identifying potentially inaccurate gTLD WHOIS contact data and forwarding these records to registrars for investigation and follow-up. To accomplish these tasks, ICANN initiated the development of the WHOIS Accuracy Reporting System. Throughout the development ICANN has consulted and collaborated with the community. 

The ARS is intended to lead to improvements over time in the accuracy of WHOIS data, which will be examined in subsequent ARS reports.


ICANN's mission is to ensure a stable, secure and unified global Internet. To reach another person on the Internet you have to type an address into your computer - a name or a number. That address has to be unique so computers know where to find each other. ICANN coordinates these unique identifiers across the world. Without that coordination we wouldn't have one global Internet. ICANN was formed in 1998. It is a not-for-profit public-benefit corporation with participants from all over the world dedicated to keeping the Internet secure, stable and interoperable. It promotes competition and develops policy on the Internet's unique identifiers. ICANN doesn't control content on the Internet. It cannot stop spam and it doesn't deal with access to the Internet. But through its coordination role of the Internet's naming system, it does have an important impact on the expansion and evolution of the Internet. For more information please visit: www.icann.org.