reliability
- 1The quality of being dependable, trustworthy, and consistent in performance or behavior.
The reliability of the new engine impressed every reviewer.
Voters questioned the candidate's reliability after several broken promises.
Similardependability
Oppositeunreliability
- 2The measurable length of time a device or system operates before it fails.
The reliability of the new turbine exceeded the manufacturer's projections.
Field data showed the sensor's reliability dropping sharply in extreme cold.
Similardependability, durability
Oppositeunreliability
Note
Engineering turns trust into a stopwatch. Reliability is how long a component keeps working before it fails, usually expressed as mean time between failures and judged under stated operating conditions. Unlike the testing sense, where the measurement itself must be consistent, here the machine is what is under scrutiny. A figure means little without the conditions it was measured in.
- 3The degree to which a test or measurement gives the same result when repeated under the same conditions.
The questionnaire's reliability was confirmed when repeated administrations produced nearly identical scores.
Researchers reported low reliability for the rating scale across different observers.
Similarconsistency, repeatability, reproducibility
Oppositeunreliability, inconsistency
Note
Educational testing narrows trustworthiness down to consistency. A reliable measure gives the same reading each time it is repeated, whether or not that reading is correct. Correctness is the business of validity, its constant partner, which asks whether an instrument measures what it claims to. A scale that always reads two pounds heavy is perfectly reliable and still not valid.
Practice
Can you tell the meanings of reliability apart? Answer 4 quick questions from this page, or write your own sentence and AI will check it.
Origin
Formed from the adjective "reliable" combined with the suffix "-ity".