Consistency has three technical meanings:

• In mathematics and logic, as well as in theoretical physics, it refers to the proposition that a formal theory or a physical theory contains no contradictions. See consistency proof.
• In statistics, consistency (statistics) refers to a property of estimators.
• In decision theory, a voting system is called "consistent" if and only if it guarantees that whenever option A is the winner both in district 1 and district 2 then option A must also be the winner in the combined district.