Usability in Civic Life: Voting and Usability
US Voting System Standards for Usability and Accessiblity
In the US, voting systems are selected and purchased by the states and local election officials. A new law, passed in 2002, required a new agency, the Election Assistance Commission (EAC), to create voting system standards and to set up a program to test voting systems against those requirements. States may choose to adopt these standards thus, they are called "voluntary guidelines". (More on US elections.)
The 2005 Voluntary Voting System Guidelines (VVSG)
The current guidelines went into effect in January 2007. They include requirements for both usability and accessibility. This is the first time usability has been included in voting system standards, and accessibility requirements are significantly expanded.
The VVSG 2005 usability and accessibilty requirements include:
- Usability testing
- Manufacturers are required to conduct summative usability tests with representative, partially sighted, and blind individuals, and individuals lacking fine motor control
- Usability requirements for:
- Functional capabilities for voting
- Alternative languages as required by law
- Cognitive issues
- Perceptual issues
- Interaction issues
- Privacy and privacy at the polls, including no recording of the use of any alternative format
- General Accessibilty requirements for:
- Equivalence of the alternate format
- No requirement that voters provide personal assistive devices
- Accessiblity requirements for vision
- An adjustible visual display
- Audio synchronized to the visual display
- Navigation of the audio ballot
- An adjustible audio volume and speed
- Accessibility requirements for dexterity
- No tight grasping or twisting
- No use of the body in an electrical circuit (eg, for touch screens)
- Accessibility requirements for mobility
- Reach and touch requirements harmonized with the ADA Architectural Guidelines (ADAAG)
- Accessibilty requirements for hearing and speech
- All sounds accompanied by a visual cue
- No voter speech may be required
Work on the next version of the VVSG
On September 6, 2007, the EAC received the TGDC Recommended Guidelines for an update to the VVSG. This draft was made available for public comment in October 2007. Please see the EAC web site for information about the current status.
The most significant proposed changes from VVSG 2005 are new performance requirements, requiring systems to meet benchmarks for effectiveness (accuracy), and report results for efficiency and satisfaction (confidence).
These benchmarks are tested in human peformance tests, using the Voter Performance Protocol.
"Usability is defined generally as a measure of the effectiveness, efficiency, and satisfaction achieved by a specified set of users with a given product in the performance of specified tasks. In the context of voting, the primary user is the voter…
"Additional requirements for task performance are independence and privacy: the voter should normally be able to complete the voting task without assistance from others, and the votes should be private. Lack of independence or privacy may adversely affect effectiveness (e.g., by possibly inhibiting the voter's free choice) and efficiency (e.g., by slowing down the process).
"General usability is covered by both high-level performance-based requirements (in this section) and design requirements (in following sections). Whereas the latter require the presence of specific features generally thought to promote usability, the former directly address metrics for effectiveness (e.g., correct capture of voter selections), efficiency (e.g., time taken to vote), and satisfaction. The voting system is tested by having groups of people (representing voters) attempt to perform various typical voting tasks. The requirement is met only if those tasks are accomplished with a specified degree of success." [Section 3.2.1]
The draft VVSG defines three benchmarks for accuracy:
- Total Completion Score - the proportion of users who successfully cast a ballot (whether or not the ballot contains erroneous votes). Failure to cast a ballot might involve problems such as a voter simply "giving up" during the voting session because of an inability to operate the system, or a mistaken belief that one has successfully operated the casting mechanism.
- Perfect Ballot Index - the ratio of the number of cast ballots containing no erroneous votes to the number of cast ballots containing one or more errors (either a vote for an unintended choice, or a missing vote).
- Voter Inclusion Index - a measure of both voting accuracy and consistency. It is based on mean accuracy and the associated standard deviation. Accuracy per voter depends on how many "voting opportunities" within each ballot are performed correctly. A low value for the standard deviation of these individual accuracy scores indicates higher consistency of performance across voters.
Other new requirements include:
- Several guidelines from the accessibility section in VVSG 2005 are moved into the general usability requirements (and therefore apply to all systems)
- Guidelines for writing instructions in plain language
- More detailed requirements to support usable ballot design
- Consideration of usability for poll workers
- More careful differentiation between the requirements for editable (eg, electronic) and non-editable (eg, paper) voting interfaces
- Human factors requirements for independent voter-verifiable records (including VVPAT)