Three questions most people can't answer
There's a three-question finance quiz that researchers have been handing out for two decades, and it makes adults look bad in every country that runs it. Not "adults could always learn more" bad. "Fewer than a third of Americans pass" bad. The newest data, collected in 2021, has a detail that keeps me up at night: people got the inflation question wrong while standing in the middle of an inflation spike.
The paper is Lusardi and Streeter, "Financial literacy and financial well-being: Evidence from the US", Journal of Financial Literacy and Wellbeing, 2023, using the 2021 National Financial Capability Study.
TL;DR: The three boring questions (compound interest, inflation, diversification) predict financial outcomes better than almost anything else you could teach. Passing all three tracks −6.3 percentage points of financial fragility and −3.8 points of too-much-debt, and the strongest single link to planning for retirement. Fewer than 30% pass.
Take the quiz
Answer honestly, no scrolling ahead.
Q1. You have $100 in a savings account earning 2% per year. After 5 years, do you have more than $102, exactly $102, or less than $102?
Q2. Your savings account pays 1% per year and inflation is 2% per year. After one year, can you buy more, the same, or less than today with the money in that account?
Q3. True or false: buying a single company's stock usually provides a safer return than a stock mutual fund.
Answers, respectively: more, less, false. If you got all three, congratulations, you're in under 30% company. Now keep reading anyway, because the interesting part is who doesn't.
The 2021 scoreboard
| Question | Correct | Wrong | Don't know |
|---|---|---|---|
| Compound interest | 69.4% | 14.2% | 15.4% |
| Inflation | ~54% | 22.7% | 23.1% |
| Diversification | worst topic | not reported | over 45% |
Barely 30% answered all three correctly, about 20% got none right, and the youngest cohort passed at just 14%. On diversification, the single most common answer wasn't wrong, it was "don't know", from nearly half the country.
What passing is worth
The researchers regressed real outcomes on literacy scores with full demographic controls, age, education, income, employment, all of it. People who passed all three were:
- 6.3 percentage points less likely to be financially fragile (couldn't cover a $2,000 shock)
- 3.8 percentage points less likely to report too much debt
- and literacy had the strongest single association with planning for retirement of anything measured
Correlation, not proof of causation, and the paper is honest about that. Still, this is one of the most replicated patterns in the field.
Why the inflation number is the story
69% getting compound interest right feels fine until you compare it to the inflation question. In 2021, prices were visibly climbing at the grocery store, and yet 46% of respondents couldn't correctly say whether a 1% account beats 2% inflation (22.7% wrong, 23.1% wouldn't guess).
The paper's sharpest finding is the overconfidence asymmetry: self-assessed knowledge exceeds actual knowledge most at the bottom of the distribution. The people most sure they understand inflation were the people missing the inflation question, mid-spike, with groceries as a cheat sheet in their cart.
If a money topic feels obvious, that's precisely where your untested knowledge is most likely to be wrong. Test the feeling.
Bob and the two savings accounts
Bob holds $1,000 for 20 years. At 2%, he ends with about $1,486. At 5%, about $2,653. Same Bob, same decade, the only difference is whether he understood Q1 well enough to ask what rate he was getting. People who fail the compounding question don't just mis-forecast balances, they stop asking the questions that matter, like why the bank's "high interest" savings account pays a fraction of what a plain GIC does.
The honest caveats
It's a cross-sectional survey, so literacy and good outcomes travel together without proof of which causes which (the broader literature, including meta-analyses, supports the direction). The Big Three is a coarse 0-to-3 score that skips mortgages, insurance and tax. "Don't know" answers mix genuine ignorance with test-shyness. All fair. The pass rate is still under 30%.
What to actually do
- If you missed one of the three above, that's the curriculum. Spend an evening on it, not a weekend on crypto tax strategy.
- Before teaching anyone anything advanced, your kids included, run them through the Big Three. The data says the foundation is usually what's missing.
- Diversification is the worst-scoring topic and the easiest fix: one total-market fund and the question dissolves.
- Schedule your own re-quiz once a year. The feeling of "obvious" doesn't update itself.
How strong is the evidence?
Scale: Strong = replicated across multiple peer-reviewed studies · Moderate = one solid peer-reviewed study or consistent findings in limited settings · Suggestive = working paper, small samples, or not yet replicated · Thin = non-peer-reviewed source or conflicting evidence.
| Claim in this post | Backing | Strength |
|---|---|---|
| Fewer than 30% of Americans pass the Big Three; diversification is the worst topic | Lusardi & Streeter (peer-reviewed, 2021 NFCS) plus two decades of prior waves and country replications | Strong — among the most replicated facts in household finance, stable across countries and years |
| People missed the inflation question during an actual inflation spike | this study's 2021 wave | Moderate — peer-reviewed, one survey wave, but the timing detail is verifiable fact |
| Passing all three tracks −6.3pp financial fragility, −3.8pp too-much-debt, strongest link to retirement planning | this study | Moderate — peer-reviewed but cross-sectional and correlational; the specific coefficients belong to this sample |
| Self-assessed knowledge exceeds actual knowledge most at the bottom | this study | Moderate — one peer-reviewed study; related overconfidence findings exist in adjacent literatures but not this exact result |
| Bob's $1,486 vs $2,653 at 2% vs 5% | arithmetic | n/a — calculator math, not a study claim |
Next steps
- Doing money beats knowing money — why the knowledge alone refuses to convert into outcomes.
- The skim view: digest + full PDF — every claim above, one tap from the source.
- The paper itself — Lusardi and Streeter, Journal of Financial Literacy and Wellbeing, 2023.