Sources and Credits

On this page

1. Which sources do our pages use?
2. Which software is the site built with?
3. Which fonts are used?
4. Whose trademarks are mentioned?
5. How can you reach us about credits?
6. Related pages

This page describes how IQ Score Level works. It is not legal advice.

IQ Score Level is built on the work of others: researchers, publishers who share their materials, and open-source developers. This page credits them.

Which sources do our pages use?

Our pages use primary sources: research papers, test publishers’ materials, official organization pages and legal texts. Every fact is logged in our facts register before it is used. Here is every reference cited across the site:

• American Association on Intellectual and Developmental Disabilities. Defining criteria for intellectual disability. aaidd.org/intellectual-disability/definition
• American Mensa Supervisory Psychologist. The question of genius. pb.us.mensa.org/resources/questionofgenius.html
• American Mensa. Qualifying test scores. us.mensa.org/join/testscores
• American Mensa. Testing (admission test sessions and fees). us.mensa.org/join/testing
• American Psychological Association. APA Dictionary of Psychology: Flynn effect. dictionary.apa.org/flynn-effect
• American Psychological Association. APA Dictionary of Psychology: IQ; deviation IQ; standard error of measurement. dictionary.apa.org
• American Psychological Association. Psychologist Locator. locator.apa.org
• Bethlehem, J. (2010). Selection bias in web surveys. International Statistical Review, 78, 161 to 188. doi:10.1111/j.1751-5823.2010.00112.x
• Bock, R. D. and Mislevy, R. J. (1982). Adaptive EAP estimation of ability in a microcomputer environment. Applied Psychological Measurement, 6, 431 to 444. doi:10.1177/014662168200600405
• Bratsberg, B. and Rogeberg, O. (2018). Flynn effect and its reversal are both environmentally caused. Proceedings of the National Academy of Sciences, 115, 6674 to 6678. doi:10.1073/pnas.1718793115
• Carpenter, P. A., Just, M. A. and Shell, P. (1990). What one intelligence test measures: a theoretical account of the processing in the Raven Progressive Matrices Test. Psychological Review, 97, 404 to 431. doi:10.1037/0033-295X.97.3.404
• Cowan, N. (2001). The magical number 4 in short-term memory: a reconsideration of mental storage capacity. Behavioral and Brain Sciences, 24, 87 to 114. doi:10.1017/S0140525X01003922
• Eriksen, B. A. and Eriksen, C. W. (1974). Effects of noise letters upon the identification of a target letter in a nonsearch task. Perception and Psychophysics, 16, 143 to 149. doi:10.3758/BF03203267
• Fischer, G. H. (1973). The linear logistic test model as an instrument in educational research. Acta Psychologica, 37, 359 to 374. doi:10.1016/0001-6918(73)90003-6
• Google AdSense Help. Consent requirements for the EEA, UK and Switzerland. support.google.com/adsense/answer/13554116
• Google AdSense Help. Required content for your privacy policy. support.google.com/adsense/answer/1348695
• Google AdSense Help. US state regulations messages. support.google.com/adsense/answer/10961479
• Google Search Central. Creating helpful, reliable, people-first content. developers.google.com/search/docs/fundamentals/creating-helpful-content
• Google. How Google uses cookies in advertising. policies.google.com/technologies/ads
• Hubner, R. and Tobel, L. (2019). Conflict resolution in the Eriksen flanker task: similarities and differences to the Simon task. PLOS ONE, 14, e0214203. doi:10.1371/journal.pone.0214203
• Jaeger, J. (2018). Digit Symbol Substitution Test: the case for sensitivity over specificity in neuropsychological testing. Journal of Clinical Psychopharmacology, 38, 513 to 519. doi:10.1097/JCP.0000000000000941
• Jaeggi, S. M., Buschkuehl, M., Perrig, W. J. and Meier, B. (2010). The concurrent validity of the N-back task as a working memory measure. Memory, 18, 394 to 412. doi:10.1080/09658211003702171
• Kessels, R. P. C., van Zandvoort, M. J. E., Postma, A., Kappelle, L. J. and de Haan, E. H. F. (2000). The Corsi Block-Tapping Task: standardization and normative data. Applied Neuropsychology, 7, 252 to 258. doi:10.1207/S15324826AN0704_8
• Kirchner, W. K. (1958). Age differences in short-term retention of rapidly changing information. Journal of Experimental Psychology, 55, 352 to 358. doi:10.1037/h0043688
• Legal Information Institute, Cornell Law School. 17 U.S. Code 512, Limitations on liability relating to material online. law.cornell.edu/uscode/text/17/512
• Legal Information Institute, Cornell Law School. 34 CFR 300.301, Initial evaluations. law.cornell.edu/cfr/text/34/300.301
• Matzen, L. E., Benz, Z. O., Dixon, K. R., Posey, J., Kroger, J. K. and Speed, A. E. (2010). Recreating Raven's: software for systematically generating large numbers of Raven-like matrix problems with normed properties. Behavior Research Methods, 42, 525 to 541. doi:10.3758/brm.42.2.525
• Mensa International. Getting your IQ tested: FAQs. mensa.org/getting-your-iq-tested-faqs
• Mensa International. Mensa IQ Challenge. mensa.org/mensa-iq-challenge
• Mensa International. What is IQ? mensa.org/what-is-iq
• Mensa Norway. IQ test. mensa.no/iq-test
• Miller, G. A. (1956). The magical number seven, plus or minus two: some limits on our capacity for processing information. Psychological Review, 63, 81 to 97. doi:10.1037/h0043158
• Monaco, M., Costa, A., Caltagirone, C. and Carlesimo, G. A. (2013). Forward and backward span for verbal and visuo-spatial data: standardization and normative data from an Italian adult population. Neurological Sciences, 34, 749 to 754. doi:10.1007/s10072-012-1130-x
• National Association for Gifted Children. What is giftedness? nagc.org/what-is-giftedness
• Owen, A. M., McMillan, K. M., Laird, A. R. and Bullmore, E. (2005). N-back working memory paradigm: a meta-analysis of normative functional neuroimaging studies. Human Brain Mapping, 25, 46 to 59. doi:10.1002/hbm.20131
• Pearson. Otis-Lennon School Ability Test, Eighth Edition (OLSAT 8).
• Pearson. Raven's 2 flyer.
• Pearson. WAIS-5 overview brochure.
• Pearson. WAIS-5 sample score report.
• Pearson. WAIS-IV sample score report (traditional descriptive classification).
• Pearson. WISC-V descriptive classification (training handout by Gloria Maccow) and WISC-V sample interpretive report.
• Pearson. WISC-V product page (ages).
• Pearson. WPPSI-IV brochure.
• PRO-ED and PAR. Stanford-Binet Intelligence Scales, Fifth Edition (SB5) product pages and user guide.
• Regulation (EU) 2016/679 (General Data Protection Regulation), Articles 6 and 8. eur-lex.europa.eu
• Riverside Insights. Cognitive Abilities Test (CogAT).
• Russell Warne. The search for Albert Einstein's IQ. russellwarne.com (review of published claims with page citations).
• Scarpina, F. and Tagini, S. (2017). The Stroop Color and Word Test. Frontiers in Psychology, 8, 557. doi:10.3389/fpsyg.2017.00557
• Scharfen, J., Peters, J. M. and Holling, H. (2018). Retest effects in cognitive ability tests: a meta-analysis. Intelligence, 67, 44 to 66. doi:10.1016/j.intell.2018.01.003
• Simons, D. J., Boot, W. R., Charness, N., Gathercole, S. E., Chabris, C. F., Hambrick, D. Z. and Stine-Morrow, E. A. L. (2016). Do "brain-training" programs work? Psychological Science in the Public Interest, 17, 103 to 186. doi:10.1177/1529100616661983
• Steger, D., Schroeders, U. and Gnambs, T. (2020). A meta-analysis of test scores in proctored and unproctored ability assessments. European Journal of Psychological Assessment, 36, 174 to 184. doi:10.1027/1015-5759/a000494
• Stroop, J. R. (1935). Studies of interference in serial verbal reactions. Journal of Experimental Psychology, 18, 643 to 662. doi:10.1037/h0054651
• The Nobel Prize. Albert Einstein, biographical. nobelprize.org
• US Federal Trade Commission. Complying with COPPA: frequently asked questions. ftc.gov
• Wessel, J. R. (2018). Prepotent motor activity and inhibitory control demands in different variants of the go/no-go paradigm. Psychophysiology, 55, e12871. doi:10.1111/psyp.12871
• Wolfe, J. M. (2020). Visual search: how do we find what we are looking for? Annual Review of Vision Science, 6, 539 to 562. doi:10.1146/annurev-vision-091718-015048
• Woods, D. L., Wyma, J. M., Yund, E. W., Herron, T. J. and Reed, B. (2015). Factors influencing the latency of simple reaction time. Frontiers in Human Neuroscience, 9, 131. doi:10.3389/fnhum.2015.00131

Pages cite these in their own reference lists. Our editorial policy explains how sources are chosen.

Which software is the site built with?

The site is built with open-source software. These are the libraries that the site itself depends on, with their licenses as stated by each package:

We thank their authors. Tools used only to build and test the site are listed in the project’s own files.

Which fonts are used?

The site uses three open-source fonts. We serve them from our own server, so no font is loaded from another company.

• Inter, for text, by The Inter Project Authors.
• Source Serif 4, for main headings and scores, by Adobe.
• JetBrains Mono, for code, by The JetBrains Mono Project Authors.

All three are released under the SIL Open Font License. A copy of each license is served with the fonts, in the fonts folder of this site.

Whose trademarks are mentioned?

Test names and organization names are trademarks of their owners. We use them only to describe the tests and groups they belong to.

Where we have read the owner’s own notice, we name the owner:

• WAIS, Wechsler, Wechsler Adult Intelligence Scale, PsychCorp and Q-global are trademarks of Pearson Education, Inc. or its affiliates.
• Ravens is a trademark of Pearson.
• CogAT is a registered trademark of Riverside Insights.

Other names on this site, such as Mensa, Stanford-Binet, WISC, WPPSI, OLSAT and NNAT, are trademarks of their respective owners.

How can you reach us about credits?

If we have missed a credit or named an owner wrongly, please tell us through the contact page. We will fix it. Our about page explains who runs the site.

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