Xavier Jouve, Ph.D. — Psychometrician & Head of Research

Cognitive Assessment Instruments

Xavier has designed and validated seven cognitive assessment instruments available through Cogn-IQ, collectively normed on over 13,000 examinees:

Articles on PsychoLogic

Xavier has authored 71 articles covering psychometrics, intelligence theory, IQ testing, and statistical methods:

Technological Advances in Psychology (5)

Computerized Adaptive Testing Explained: How Modern Tests Adapt to You (2026)

Simulated IRT Dataset Generator v1.00 at Cogn-IQ.org (2023)

Sequential Generalized Likelihood Ratio Tests for Item Monitoring (2023)

Computerized Adaptive Testing: Exploring Enhanced Techniques (2023)

Building Resistance Against Online Misinformation (2021)

Psychological Measurement and Testing (25)

How to Interpret IQ Test Results: A Psychometrician’s Guide (2026)

WAIS-IV vs. WAIS-V: What Changed and Why It Matters for Your IQ Score (2026)

Do IQ Tests Measure What They Claim? Common Criticisms Answered (2026)

IQ Test Accuracy: How Reliable Are Online IQ Tests vs. Professional Assessments? (2026)

Psychometrics: The Science of Psychological Measurement (2025)

Tellegen & Briggs Formula 4 Calculator at Cogn-IQ.org (2023)

The Complex Journey of the WAIS: Insights and Transformations (2023)

Overclaiming: Insights from 40,000 Teens (2023)

Explore the validity and reliability of the JCTI, and its strong correlations with SAT Math and RIST scores. (2023)

Assessing the Reliability of JCCES in Measuring Crystallized Cognitive Skills (2023)

Assessing Nonverbal Intelligence: Insights from the JCFS (2023)

A Look at Verbal Abilities With The JCWS (2023)

Assessing Verbal Intelligence with the IAW Test (2023)

Evaluating the NIH Toolbox for Cognitive Change in Intellectual Disabilities (2023)

Validity of WISC-V Profiles of Strengths and Weaknesses (2023)

How Continuous Norming Outperforms Conventional Methods (2021)

Introducing the NCS-6: A Streamlined Measure of Need for Cognition (2020)

Evaluating Nonmemory-Based PVTs for More Accurate Neuropsychological Assessments (2020)

Evaluating Short-Form IQ Estimations for the WISC-V (2020)

An alternative Cattell-Horn-Carroll (CHC) factor structure of the WAIS-IV (2013)

Stanford-Binet & WAIS IQ Differences in Adults with Intellectual Disability (2010)

What does the WAIS-IV measure? (2010)

Age-Based Reliability Analysis of the Jouve Cerebrals Test of Induction (2010)

Revising the Epreuve de Performance Cognitive: Psychometric Properties of the Revised Nonverbal, Sequential Reasoning Test (2010)

Evaluating the Reliability and Validity of the TRI52: A Computerized Nonverbal Intelligence Test (2010)

Cognitive Abilities and Intelligence (20)

Sex Differences in Cognitive Abilities: What the Data Actually Shows (2026)

What Does an IQ of 130, 140, or 150 Actually Mean? (2026)

Fluid vs. Crystallized Intelligence: What They Are and Why Both Matter (2026)

The Flynn Effect: Are Humans Getting Smarter — or Dumber? (2026)

IQ vs. EQ: Which Matters More for Success in Life? (2026)

Can You Actually Increase Your IQ? What the Research Shows (2026)

SAT Scores and IQ: How Closely Are They Correlated? (2026)

What Is Considered a High IQ? Ranges, Percentiles, and What They Mean (2026)

Cognitive Ability and Optimism Bias (2023)

Decoding High Intelligence: Interdisciplinary Insights (2023)

Tracing the SAT’s Intellectual Legacy and Its Ties to IQ (2023)

Analyzing Trends in the Flynn Effect (2023)

The Plateau of Cognitive Ability Among Top Earners (2023)

Intelligence and Music Aptitude in Piano Skill Acquisition (2019)

Dissecting Cognition: Spatial vs. Abstract Reasoning? (2018)

Dissecting the Cognitive Landscape: Literary vs. Scientific Intellect (2016)

Busting the Myth: Are Blondes Really Dumb? (2016)

Gender Differences in Technical Aptitude (2011)

The Relationship Between SAT Scores and General Cognitive Ability (2010)

Dissecting Cognitive Measures in Reasoning and Language (2010)

Statistical Methods and Data Analysis (21)

A Beginner’s Guide to Item Response Theory (IRT): How Modern Tests Work (2026)

Addressing the Divide Between Psychology and Psychometrics (2024)

Interpreting Differential Item Functioning with Response Process Data (2024)

Integrating SDT and IRT Models for Mixed-Format Exams (2024)

Rotation Local Solutions in Multidimensional Item Response Models (2024)

Group-Theoretical Symmetries in Item Response Theory (IRT) (2024)

Theoretical Framework for Bayesian Hierarchical 2PLM with ADVI (2024)

Evaluating Coefficient Alpha and Alternatives in Non-Normal Data (2023)

Refining Reliability with Attenuation-Corrected Estimators (2022)

Understanding Prior Sensitivity in Bayesian Structural Equation Modeling (2020)

The Role of Item Distributions in Reliability Estimation (2020)

Evaluating Factor Retention in Exploratory Factor Analysis (2020)

Comparing Rasch and Classical Equating Methods for Small Samples (2020)

Examining the Effect of Estimation Methods on SEM Fit Indices (2020)

Exploring the Underlying Dimensions of Cognitive Abilities: A Multidimensional Scaling Analysis of JCCES and GAMA Subtests (2015)

Differentiating Cognitive Abilities: A Factor Analysis of JCCES and GAMA Subtests (2014)

Exploring the Relationship between JCCES and ACT Assessments: A Factor Analysis Approach (2014)

Optimizing Item Parameter Estimation for the Generalized Graded Unfolding Model (2011)

Identifying the Underlying Dimensions of the JCCES Mathematical Problems using Alternating Least Squares Scaling (2010)

Investigating the Relationship Between JCCES and RIAS Verbal Scale: A Principal Component Analysis Approach (2010)

Assessing the Validity and Reliability of the Cerebrals Cognitive Abilities Test (CCAT) (2010)

Meet the Team

• Priya Sharma, Ph.D. — Educational Psychology & Assessment Development
• Nuno Freitas, Ph.D. — Cognitive Neuroscience & Brain Health