Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.



The essence of interoperability is to enable various devices to work together to perform common processes and achieve shared goals. To realize this capability in election technology, means taking steps toward creating a foundation that enables common data and processes to be carried out through the entire election eco-system. The NIST efforts in interoperability focus on Common Data Formats to allow election information to move between parts of the election eco-system.   

Common Data Formats (CDFs)

NIST has led the development of CDFs to support interoperability. The first 4 CDFs are called out in the VVSG. Going beyond the VVSG-required CDFs, additional formats were developed based on two studies which identified gaps remaining in election eco-system interoperability and strategies to address them. 

CDF Specification 

Reference Implementation 

Required in VVSG 2.0 

Voter Records Interchange  


Cast Vote Records  


Election Results  


Election Event Logging  


Ballot Definition Specification No
Micro-CDF Specification No

Common Data Format Test Method

The CDF test method is a machine-executable method for testing voting CDFs. Its use is intended for voting system manufacturers, voting system test laboratories, and other members of the election community.


CDF-Related Publications


Publication Type



NIST GCR 22-034

Recommendations for Voting System Interoperability


NIST GCR 22-033

Gap Analysis for Key Interoperability Scenarios in Election Technology


NIST SP 1500-101

Election Event Logging Common Data Format Specification


NIST SP 1500-102

Voter Records Interchange Common Data Format Specification


NIST SP 1500-103

Cast Vote Records Common Data Format Specification


NIST SP 1500-100

Election Results Common Data Format Specification

Additional information can be found at the Interoperability GitHub site: 


NIST’s original involvement in carrying out this interoperability vision began with considerations of the need for common, non-proprietary formats for voting device interactions. Initial steps toward this idea (public format, import, export) were outlined in the original VVSG 2007 TGDC Recommendations. A larger community conversation followed in 2009, with the first NIST Common Data Format (CDF) workshop. The early days of this work involved some initial activities through working group efforts with IEEE. These efforts were eventually continued through NIST in the form of VVSG 2.0 public working groups. A number of VVSG 2.0 interoperability-specific working groups were formed to identify and prototype initial specifications and reference implementations for a set of common data formats that could cover the essential aspects of election processes. The activities in these groups focused mostly on organizing, modeling, and specifying knowledge about election processes and data. These efforts resulted in the creation of an initial set of CDFs whose draft specifications and reference implementations are located, respectively, in the NIST 1500 special publication series specifications and in related GitHub repositories (for reference UML models and XML/JSON implementations). The CDF specifications identified for inclusion in VVSG 2.0 were the Voter Records Interchange, Cast Vote Records, Election Results, and Election Event Logging specifications. Implementation and adoption of these CDFs through VVSG 2.0 will represent a major initial step toward realization of the interoperability vision. 

Following the release of VVSG 2.0, NIST continued its interoperability research using working groups to help develop the two additional CDFs. Information about the groups is available on the History and Archive section.

Created July 21, 2017, Updated September 27, 2023