IQ, explained with sources

Plain-English guides to IQ: what scores mean, how tests work, how accurate they are, and what the research says, with the sources behind every claim.

IQ scores and what they mean

What IQ is, how scores are distributed, and what counts as average, high or genius.

What Is IQ? What It Means and What It Measures | My IQ Path

IQ stands for intelligence quotient: a test score scaled so the average is 100. Learn what IQ tests measure, what scores...

IQ Score Ranges: What Is a Good IQ Score? | My IQ Path

What is a good IQ score? See the IQ scale band by band, the share of people in each range, and why labels like High Aver...

Average IQ by Age: Why It's Always 100 | My IQ Path

The average IQ at every age is 100, because IQ tests are scored against same-age peers. Here is what does change with ag...

What Is a Genius IQ? Scores, Rarity, Myths | My IQ Path

There is no scientific genius IQ cut-off. See how rare scores of 130, 140, 145 and 160 are, what counts as gifted, and w...

The IQ Bell Curve: How IQ Scores Are Distributed | My IQ Path

How the IQ bell curve works: mean 100, standard deviation 15, the 68-95-99.7 rule in IQ points, and how to turn any IQ s...

Signs of High Intelligence: What the Evidence Says

Which signs of high intelligence hold up in research, from fast learning to vocabulary, and which viral ones, like messy...

The g Factor: What General Intelligence Means | My IQ Path

The g factor is the general ability shared by all mental tests. Learn how Spearman found it, how CHC theory organizes ab...

Types of Intelligence: Fluid vs Crystallized | My IQ Path

The types of intelligence psychologists measure: fluid vs crystallized, working memory, speed and more, plus what resear...

Multiple Intelligences Theory: The Evidence | My IQ Path

Gardner's multiple intelligences theory explained: the 8 intelligences, why schools embraced it, what testing found, and...

IQ vs EQ: What Each Predicts | My IQ Path

IQ vs EQ explained: what emotional intelligence is, ability vs trait EI, what each predicts at work and in relationships...

Can IQ Change? What Raises It and What Doesn't | My IQ Path

IQ can change, but less than ads suggest. Schooling adds about 1 to 5 points per year, brain games rarely transfer, and ...

Taking an IQ test

How tests are built and scored, how accurate they are, what the questions look like, and how to read your result.

Types of IQ Test Questions, With Examples | My IQ Path

The main types of IQ test questions, from matrices and analogies to number series, rotation, memory span and speed, each...

How IQ Is Calculated: Ratio vs Deviation IQ | My IQ Path

How IQ is calculated: the old ratio formula, the modern deviation IQ, what a norming sample does, why tests are re-norme...

What Does My IQ Score Mean? IQ Percentiles | My IQ Path

What your IQ score means: percentile vs percent correct, an IQ-to-percentile table, confidence intervals, uneven domain ...

Are IQ Tests Accurate? Reliability and Validity | My IQ Path

Are IQ tests accurate? How reliable clinical tests are, what scores predict, where they fall short, how online tests com...

Free vs Paid IQ Tests: Which Are Worth It? | My IQ Path

Free vs paid IQ tests: how to judge any online test, red flags to avoid, short vs full tests, and when a clinical assess...

How to Prepare for an IQ Test | My IQ Path

How to prepare for an IQ test without skewing the result: sleep, logistics, formats and pacing, and why drilling practic...

Intelligence and society

Education, genetics, history, the Flynn effect and what national comparisons can and cannot show.

Average IQ by Country: What the Data Shows | My IQ Path

Why national IQ rankings are unreliable, what the US average of 100 really means, and what credible cross-country data s...

Is Intelligence Genetic? Nature vs Nurture | My IQ Path

Is intelligence genetic? What twin, adoption and DNA studies show about IQ heritability, why it rises with age, and how ...

The Flynn Effect: Are People Getting Smarter? | My IQ Path

The Flynn effect is the rise in IQ scores of about 3 points per decade during the 20th century. What caused it, and why ...

IQ and Education: Does School Raise IQ? | My IQ Path

Does education increase IQ? The best evidence says yes, by about 1 to 5 points per extra year. Plus how well IQ predicts...

History of IQ Testing: Who Invented the IQ Test | My IQ Path

Who invented the IQ test? The history from Binet and Simon in 1905 through the Stanford-Binet, Army Alpha, Wechsler, Rav...

IQ, work and income

What the research says about IQ, occupations, earnings and cognitive tests in hiring.