Why Most Drivers Really Can Be Better Than Average
The short version: most drivers think they're better than average, and if 'average' means the mean, most of them can actually be right. A few terrible drivers drag the mean down. Better than the median, though, is a seat only half of us can sit in.
"I'm a better driver than average," says Uncle Gary, who has never once driven home from the pub, which is statistically the best decision in this whole article.
Everyone at the table laughs, because everyone thinks the same about themselves. Psychologists have found this for decades: in a classic 1981 study most drivers rated themselves as more skilful than the average driver in their group, and a 2023 replication found the same.
The usual conclusion: we're all deluded. The fun part: maths says it isn't necessarily impossible.
One terrible driver is enough
Take the ten drivers in Gary's family and count their accidents over the last ten years. Nine of them have had none. Cousin Kevin has had ten. (The lamp post outside the bowling alley has its own nickname.)
| Measure | Accidents per driver |
|---|---|
| Mean (add up and divide) | 10 ÷ 10 = 1.0 |
| Median (the one in the middle) | 0 |
The mean is 1 accident per driver. Nine out of ten family members have fewer accidents than that. So 90% of the family really is better than average, thanks entirely to Kevin.
But the median, the driver in the middle of the line, has zero accidents. Nobody can beat that. By definition, at most half of any group can be above the median.
Accidents in ten years, ten family drivers
So which "average" are we talking about?
When the numbers are lopsided, with a few extreme values at one end, the mean and the median split apart. The mean gets pulled toward the extremes. The median stays with the typical person.
- Accidents, debts, house prices and incomes are all lopsided like this.
- When someone says "the average", it's worth asking: mean or median?
- In surveys, "better than average" usually means better than the typical person, which is the median. And that's where most of us are kidding ourselves.
Where it costs you money
"The average trader made money this year" can be true while most traders lost money. A few huge winners can pull the mean up while the median person is down. When someone quotes an average return, ask what happened to the person in the middle.
The moral
You might really be better than average. Just check whether there's a Kevin in the sample.
The family accident numbers are an illustration, not data. The driver studies are linked above. Educational content, not financial advice.