What is the Most Accurate IQ Test?

What is the most accurate IQ test? No single “best” exists—it depends on your needs. Discover the top professional options: WAIS, Stanford-Binet, Woodcock-Johnson, and trusted online RIOT.

Dr. Russell T. WarneChief Scientist

When people search for "the most accurate IQ test," they're usually looking for a definitive answer, a single test that stands above all others. Unfortunately, that's not how psychological testing works. There is no single "most accurate" IQ test, just as there's no single "most accurate" medical test. The accuracy of an IQ test depends on several factors: who is taking it, what the score will be used for, and how the test is administered.

That said, some IQ tests are far more accurate than others, and understanding what makes a test accurate can help examinees and practitioners identify which tests are worth the time and expense needed to administer them.

Characteristics of accurate IQ tests

Professional IQ tests share several characteristics that contribute to their accuracy:

Created by experts: Developing a psychological test requires years of education and expertise in statistics, cognitive psychology, and measurement theory. Tests created by amateurs or anonymous individuals cannot provide trustworthy scores.

Based on established theory: The most accurate IQ tests are grounded in empirically supported scientific theories of intelligence, such as the Cattell-Horn-Carroll (CHC) theory, which guides decisions about what abilities to measure and how to structure the test.

Representative norm samples: An IQ test's norm sample, which is the group of people whose performance serves as the comparison standard, must represent the population the test is designed for. If norms are based on a self-selected group of internet users who sought out an IQ test, scores will be distorted.

Documented psychometric properties: Legitimate test creators publish technical information about reliability, validity evidence, and norm sample characteristics. This information may appear in a test manual, technical reports, or peer-reviewed publications.

Peer review and independent evaluation: Search for the test name in Google Scholar. If the test appears in multiple peer-reviewed studies, it indicates the scientific community has examined and used it.

The most accurate individually administered IQ tests

For individually administered IQ tests where a trained psychologist tests one person at a time, several tests stand out:

The gold-standard for intelligence tests are professionally-developed tests that are administered one-on-one by a psychologist or other credentialed examiner. Tests like the Woodcock-Johnson Tests of Cognitive Abilities, the Wechsler Adult Intelligence Scale, and the Stanford-Binet Intelligence Scale are examples of this kind of test.

These tests provide highly accurate scores and are suitable for high-stakes, irreversible decisions that permanently impact someone’s life, such as legal proceedings. They are also useful for diagnosis and other clinical purposes, too.

Accurate group-administered and online IQ tests

Individually administered tests have the disadvantage of being time- and labor-intensive. For over 100 years, psychologists have created group-administered tests that can be used to measure IQ much more efficiently. These tests are often used in schooling, the military, and in employment settings. There are many group-administered tests available, including the Cognitive Abilities Test (CogAT), the Otis-Lennon School Ability Test, and the Armed Services Vocational Aptitude Battery (ASVAB).

For online testing, the landscape is more complicated. The internet is flooded with IQ tests created by amateurs that provide wildly inaccurate scores. However, the Reasoning and Intelligence Online Test (RIOT) is the first online IQ test designed to meet the same technical and ethical standards as traditional face-to-face tests. Created by Dr. Russell T. Warne, a researcher with over 15 years of experience in intelligence research, the RIOT includes a representative norm sample of English-speaking adults. The test also received external expert review during development, and has detailed technical documentation.

Tests to avoid

Free online IQ tests are almost universally unreliable. These tests’ typically proper norm samples and validity evidence. Many are designed more to generate website traffic or collect user data than to provide meaningful scores.

So which test should you take?

There is no one best test that is always preferred for everyone for every purpose. The best test for an examinee depends on their characteristics and their situation.

For high-stakes decisions, individually-administered tests are the most defensible choice. For purposes that are short-term (e.g., a few years or less) or which can be revisited in the future, group-administered tests or a test like the RIOT are appropriate. Regardless of the purpose, it is essential that the administrator ensure that the examinee belongs to the population that the test is designed for.

Generally, though, the key to choosing a suitable test is to look for tests created by identified experts, backed by technical documentation, evaluated by independent scientists, and normed on representative samples. These characteristics indicate accuracy regardless of the specific test name.

Watch “Are IQ Tests Accurate?” on the Riot IQ YouTube channel to learn what truly separates a reliable IQ test from the rest.