IQ Test Reddit: What r/cognitiveTesting Actually Built, and How Good It Is

IQ Test Reddit: Why CORE Gets Recommended So Often

"IQ test Reddit" isn't really about scattered comment threads — it converges heavily on one specific, active community: r/cognitiveTesting, a subreddit dedicated to cognitive testing discussion. What distinguishes it from a typical review-aggregator site is that its most visible recommendation isn't a link to an existing test — it's a test the community built and continues to develop itself. That test is currently CORE, which describes itself as developed by prominent members of the r/cognitiveTesting community. It replaced an earlier project, CAIT (Comprehensive Adult Intelligence Test, built by Reddit user u/EqusB and modeled on the WAIS-IV), which CognitiveMetrics now presents as CORE's predecessor rather than an actively recommended current test. A note on how to read everything that follows: the validity data below comes from CognitiveMetrics itself, describing its own test. That's genuinely more transparent than the vast majority of free IQ tests, which publish no methodology at all — but it's self-reported, not independently peer-reviewed or audited by a third party. Treat the numbers as "here's what the test's own developers found," not as an outside seal of approval.

What CORE actually measures

CORE is built on the Cattell-Horn-Carroll (CHC) theory of intelligence, the dominant framework in contemporary psychometrics, and is structured around six indices: Verbal Comprehension, Fluid Reasoning, Visual Spatial, Quantitative Reasoning, Working Memory, and Processing Speed. CognitiveMetrics offers three testing tiers depending on how much time someone wants to spend:

That range of options — from a quick screen to a genuinely lengthy full battery — is a meaningfully different structure than the single 10-to-15-minute quiz most free "IQ test" sites offer.

What the published validity data actually shows

This is the part worth taking seriously, because it's rare for a free test to publish it at all — while keeping in mind this is the developers reporting on their own test. CognitiveMetrics released a preliminary technical report (version 0.2, dated December 2025) analyzing data from 4,723 participants. A few of the concrete findings:

• Convergent validity: CORE's Full Scale IQ correlated with the Army General Classification Test (AGCT) at r = 0.804 (rising to r = 0.844 after correcting for indirect range restriction), and with an older GRE composite score at r = 0.756 (rising to r = 0.858 after the same correction). Worth knowing: this refers to the old GRE scoring format used before the test was revised in 2011, which CognitiveMetrics offers as one of its own comparison instruments — not the current GRE format test-takers encounter today. It's a useful internal benchmark within their platform, but not a comparison to a currently administered, independently normed exam.
• Mean score differences: Compared against the AGCT, CORE scores differed by an average of just -2.35 points; against the GRE composite, -0.73 points — both described in the report as well within normal measurement error.
• Structural fit: CognitiveMetrics reports CORE's hierarchical factor model fit statistics (CFI = 0.976, RMSEA = 0.018) directly alongside published figures for the WAIS-V (CFI = 0.97, RMSEA = 0.04) and Stanford-Binet-V (CFI = 0.94, RMSEA = 0.076). In plain terms, CFI (Comparative Fit Index) and RMSEA (Root Mean Square Error of Approximation) are statistics used to judge how well a proposed structure — in this case, CORE's six-index model — matches the patterns actually observed in the data; CFI closer to 1.0 and RMSEA closer to 0 both indicate a better-fitting model. CognitiveMetrics presents its own CFI and RMSEA as being in a similar range to those published for the WAIS-V's technical manual — that's a real, checkable statistical claim, but it describes internal model fit, not proof that CORE measures intelligence as accurately as a supervised, clinically administered WAIS session does in practice.

Where the same report flags its own limits

CognitiveMetrics doesn't just present favorable numbers — its report states its central limitation directly, without prompting: because the test is free and publicly available, and most participants likely encounter it through r/cognitiveTesting, the sample is self-selected, with a pre-existing interest in cognitive testing. That shows up in the data itself — the reported sample's mean Full Scale IQ was 123.49, well above the general-population average of 100, which the report explicitly attributes to this selection effect rather than treating the figure as representative of the wider public. That's a meaningfully more transparent disclosure than most free online tests offer. It's also a real reason to treat any individual CORE score, and the validity figures behind it, as one test-maker's own internal analysis rather than an independently confirmed, general-population result.

What this means if you're deciding whether to trust a score

If you're weighing a Reddit-community test like CORE against a full professional battery, the honest framing is that CORE's published methodology — a real technical report, stated correlations against other measures, and directly acknowledged sampling limitations — represents a genuinely unusual level of self-published transparency for a free test. It is not the same as independent, third-party validation, and it is not equivalent to a supervised psychometric evaluation administered by a licensed professional on a representative norming sample. CognitiveMetrics itself describes CORE as not intended for clinical or diagnostic use.

This is not a diagnostic or clinical tool

No free or community-built test, including CORE, substitutes for assessment by a qualified psychologist. Treat any score from an unsupervised, self-administered test as an informative estimate, not a diagnosis.

Sources

1. CognitiveMetrics — "CORE: Comprehensive Online Reasoning Exam" overview and test structure. https://cognitivemetrics.com/test/CORE
2. CognitiveMetrics — "CORE Validity: Preliminary Technical Report" (v0.2, December 2025). https://cognitivemetrics.com/test/CORE/validity
3. CognitiveMetrics — "CAIT: Comprehensive Adult Intelligence Test" (predecessor project page). https://cognitivemetrics.com/test/CAIT
4. r/cognitiveTesting — official community. https://www.reddit.com/r/cognitiveTesting/