Experts in psychometrics
Reference profiles of researchers and test developers. These are encyclopedic summaries — not endorsements, affiliations, or biographical marketing.
This page is an independent reference summary based on public sources. Subjects are not affiliated with CertifiedIQ unless explicitly stated in a primary source linked below.
Reviewed by: Scientific Review Team · Last reviewed: July 2026
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Charles Spearman
British psychologist who proposed the general intelligence factor (g) and advanced factor-analytic methods in psychology.
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David Wechsler
American psychologist who developed the Wechsler scales, including the WAIS and WISC, defining modern deviation IQ scoring for many clinical batteries.
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John C. Raven
British psychologist known for developing Raven's Progressive Matrices, a widely used non-verbal measure of fluid reasoning.
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Raymond B. Cattell
Psychologist who distinguished fluid and crystallized intelligence and developed culture-fair reasoning measures.