Auditing Use Case

The most essential purpose of post-election auditing technology is to verify election outcomes as well as how those outcomes were produced. Typically, this may be done in a completely offline manner.

A full recount occurs in the case when every voter-verified ballot that was properly cast is recounted for a given election. Such a process may be employed as a means for checking whether or not originally reported outcomes and recounted outcomes are the same. To perform full recounts is a lengthy, manual, and potentially error-prone process.

To provide evidence for the correct outcome more efficiently, one may perform various kinds of audits, such as risk-limiting audits, which do not necessarily require a full recount, but are designed to limit the risk of an incorrect election outcome when given an appropriate (representative, random) sample of an election’s voter-verified/cast paper ballots. The sample size typically depends on the reported margin of victory in the contest. If cast vote records (CVR) that can be efficiently associated with paper ballots are available, a risk-limiting audit may be performed at the ballot level by comparing the CVR to the paper ballot. If batch tallies can be easily linked to the relevant paper ballots, then multiple-ballot (batch) level comparison auditing may also be performed. If tallies can't be easily linked to the ballots they report on (e.g. if only precinct result reports are available, but ballots for a given precinct are scattered across many days of mail-in ballot batches), then a ballot polling audit can be performed.

This use case may also provide the opportunity for discussion of additional auditing types or approaches as well. Different auditing approaches may make use of different kinds of election process information and utilize different strategies in order to establish their conclusions. For example

• evidence-based elections require good evidence that the chain of custody of the paper ballots has been securely preserved.
• targeted auditing of specific audit units (individual ballots, precincts, batches or other auditable collections of ballots) based on timely reporting of results by audit unit, mark density information in Cast Vote Records, indications of breaches in chain of custody, and other evidence or claims that the audit unit deserves scrutiny
• poll book accounting or ballot reconciliation processes compare evidence of how many voters showed up at the polls or properly returned their ballots and cast votes, with the number of ballots counted. Discrepancies should be investigated, documented and factored into the overall assessment of the evidence. Secure and auditable methods of preserving event logs that document voter authorization, signature verification, ballot casting, ballot counting, etc. can be used to facilitate these forms of accounting.
• security checks can be performed on seals, seal logs and surveilance tapes, and event logs can be checked for anomalies

More information is available at

• Evidence-Based Elections: Stark and Wagner, IEEE Security and Privacy, 2012.
• Principles and Best Practices for Post-Election Audits - 2008
• Risk-Limiting Post-Election Audits: Why and How Risk-Limiting Audits Working Group, October 2012 (version 1.1)

<img alt="Title: Auditing Scenarios - Description: Image showing Auditing Scenarios. WHAT? Verify election results. HOW? Scenarios: 1. Typical-offline, manual: Fully, manually all voter-verified and cast ballots. 2. Risk-limiting. Case 1: Single-ballot auditing. Case 2: Multiple-ballot (batch) auditing. 3. Other auditing types…

Image also shows the relationship between auditing and voters, election officials, and vote tallying." src="https://collaborate.nist.gov/voting/pub/Voting/AuditingUseCase/image013…" />

(note - update image above)

Use Case Scenarios

WHAT | Verify election results

HOW | Scenarios

1. Recount - Typical-offline, manual: Fully, manually recount all voter-verified and cast ballots

2. Risk-limiting audit

   1. ballot-level comparison auditing

   2. Multiple-ballot (batch) comparison auditing

   3. Ballot polling audit

3. Ballot accounting audit

4. Chain of custody checks
5. Security checks

Request for Feedback

For each use case scenario, please address these questions:

1. Is the use case scenario in scope for the Next Generation VVSG for development of requirements that will undergo testing and certification? or
2. Is the use case scenario in scope to develop as guidelines for election officials and voting system manufacturers? or
3. Is the use case scenario not in scope for this work?
4. If different parts of the use case scenario fall in 1., 2., and/or 3. Please identify as such.
5. Is anything missing?