Reliability
Reliability is the consistency of measurement — whether repeated testing yields similar results.
Reviewed by: Scientific Review Team · Last reviewed: July 2026
Internal consistency, test-retest reliability, and inter-rater reliability are common indices. Low reliability caps validity: a noisy measure cannot precisely track true ability.
Synonyms: measurement consistency
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FAQ
What is a good reliability coefficient?
Many published IQ subtests report Cronbach's alpha above .80; context and subgroup stability matter.
Scientific sources
- APA Standards for Educational and Psychological Testing.