Grit vs IQ: Which is a Better Predictor of Success?

This article is an excerpt from the Shortform book guide to "Grit" by Angela Duckworth. Shortform has the world's best summaries and analyses of books you should be reading.

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What’s the difference between grit vs IQ? Which is a better predictor of success?

There are a few key differences between grit vs IQ. IQ is considered part of your natural abilities. Grit is developed over time, and is considered a more effective way to measure potential.

Read more about grit vs IQ and how grit can lead to more successful outcomes.

What Do the Data Show About Grit vs IQ?

As a researcher in psychology, Duckworth showed the predictive power of grit on success in a variety of fields:

  • West Point dropouts: New cadets endure an intense 7-week bootcamp called Beast Barracks. 1 in 20 drop out. The admissions criteria used for West Point, the Whole Candidate Score (which consists of SAT score, high school rank, and physical fitness), didn’t reliably predict who would drop out. In contrast, grit predicted completion better than any other predictor – candidates with 1 standard deviation higher grit were 60% more likely to finish summer training. 
  • Army Special Operations Forces: 42% of candidates withdrew during the Selection Course. Grit predicted retention.
  • Sales: Grit predicted salespeople retention better than other personality traits – extroversion, emotional stability, conscientiousness. Someone with 1 standard deviation higher grit showed 40% greater retention at the end of 6 months.
  • College GPA: Among U Penn undergrad psych majors, Grit was associated with higher GPAs, and had a stronger effect when controlling for SAT scores. 
    • Grit was associated with lower SAT scores. Possible explanation: because the lower IQ students (assuming SAT and IQ are correlated) had to have higher grit to get into U Penn.
  • Graduate degrees: adults who completed a graduate degree were grittier than those who’d only graduated from 4-year colleges.
    • Adults who completed 2-year colleges showed higher grit than 4-year colleges too. Possibly because the dropout rate at 2-year colleges is very high, so those who make it through are especially gritty. 
  • Spelling bees: grittier kids went further in the Scripps spelling bee, likely since they studied more hours and competed in more study bees. A finalist with a grit score a standard deviation higher than average was 41% more likely to advance to further rounds.

In all these studies, grit vs IQ showed that grit had little relationship to IQ score, suggesting it is an orthogonal factor

And in these studies, grit was able to predict success even after accounting for IQ, meaning it contributes to success above and beyond IQ. This shows that in grit vs IQ, IQ is not a major factor in grit.

(Shortform note: in many of these studies, IQ was shown to be a stronger predictor of success than grit was. The author doesn’t mention this in the book since it would weaken its message. Just note that grit isn’t a total replacement for talent – it explains a different dimension of success, and, as we’ll explain later, talent and grit work together to increase achievement.)

Historical Data

Historically, high-achieving people have been known to be dogged in their pursuit of achievement. Darwin wrote that “men did not differ much in intellect, only in zeal and hard work.” Darwin himself was considered as someone not of superhuman intelligence but one who persisted stubbornly in tackling a problem well after others had already moved on. This shows a consistent understanding of the difference between grit vs IQ.

In a 1926 study of accomplished figures from history, Catharine Cox inferred their IQs from their accomplishments and categorized the most eminent geniuses and the least eminent geniuses. The “most eminent geniuses” (Francis Bacon, Isaac Newton) had an average IQ of 146, and the “least eminent geniuses” (Giuseppe Mazzini, Joachim Murat) had an average IQ of 143. So IQ didn’t distinguish these two groups, but “persistence of motive” did. Cox found that high enough intelligence, combined with strong persistence, achieved more than the smartest people with less persistence. This shows that when it comes to grit vs IQ, grit is more important.

Grit vs IQ: Which is a Better Predictor of Success?

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Like what you just read? Read the rest of the world's best book summary and analysis of Angela Duckworth's "Grit" at Shortform.

Here's what you'll find in our full Grit summary:

  • How your grit can predict your success
  • The 4 components that make up grit
  • Why focusing on talent means you overlook true potential

Carrie Cabral

Carrie has been reading and writing for as long as she can remember, and has always been open to reading anything put in front of her. She wrote her first short story at the age of six, about a lost dog who meets animal friends on his journey home. Surprisingly, it was never picked up by any major publishers, but did spark her passion for books. Carrie worked in book publishing for several years before getting an MFA in Creative Writing. She especially loves literary fiction, historical fiction, and social, cultural, and historical nonfiction that gets into the weeds of daily life.

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