PCOS units are optical scan voting machines that are specifically designed and used for precinct-based vote tabulation. PCOS units are used in polling places in jurisdictions in 40 states.
What is PCOS (precinct count optical scan)?
The term PCOS (Precinct Count Optical Scan) refers to a precinct-count optical-scan voting system that scans voter-marked paper ballots at or near the polling place and tabulates their selections. It gives election, security, legal, or technical readers a specific label for the concept rather than a broader everyday meaning.
How does PCOS (precinct count optical scan) work in a voting system?
In practice, PCOS (Precinct Count Optical Scan) is applied to the technical or security purpose captured by its definition: a precinct-count optical-scan voting system that scans voter-marked paper ballots at or near the polling place and tabulates their selections. Organizations combine that function with documented procedures, authorized access, testing, monitoring, and controls appropriate to the system.
Why does PCOS (precinct count optical scan) matter for election verification?
Understanding PCOS (Precinct Count Optical Scan) matters because the concept can affect security, reliability, auditability, or trusted operation. In this glossary context, it refers to a precinct-count optical-scan voting system that scans voter-marked paper ballots at or near the polling place and tabulates their selections.
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PCOS units are optical scan voting machines that are specifically designed and used for precinct-based vote tabulation. PCOS units are used in polling places in jurisdictions in 40 states.
Cite this term
Election Security Glossary. (2026). Pcos (precinct Count Optical Scan). In Election Security Glossary. Retrieved August 21, 2026, from https://electionsecurityglossary.com/glossary/pcos-precinct-count-optical-scan
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