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Official IQ test & certification · Raven-style matrices

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

  • Charles Spearman

    British psychologist who proposed the general intelligence factor (g) and advanced factor-analytic methods in psychology.

  • David Wechsler

    American psychologist who developed the Wechsler scales, including the WAIS and WISC, defining modern deviation IQ scoring for many clinical batteries.

  • John C. Raven

    British psychologist known for developing Raven's Progressive Matrices, a widely used non-verbal measure of fluid reasoning.

  • Raymond B. Cattell

    Psychologist who distinguished fluid and crystallized intelligence and developed culture-fair reasoning measures.

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