Mean vs median
Ten people and one very rich neighbour. The mean follows the rich one; the median barely notices.
Try it
Drag the top earner’s income and watch both averages.
| Mean (“average”) | |
| Median (the middle person) |
Invented incomes for ten ordinary neighbours (18k to 48k), plus one whose income you set.
What is going on
The mean adds everything up and shares it equally, so one huge value drags it. The median is the middle person, and is unmoved by how extreme the extremes are. For skewed things such as income and wealth, the median is much closer to the typical person.
“Average” can mean mean, median or mode, and an author who wants the biggest-looking number can pick the one that suits.
How to spot it
- “The average” with no word for which average.
- Anything about income, wealth, house prices or waiting times.
- Ask: is it the mean or the median, and what does the spread look like?
The well-chosen average
Darrell Huff opened How to Lie with Statistics with the “well-chosen average”: the same town can have a mean and a median income that tell very different stories. Official statistics now routinely publish both; the UK Office for National Statistics, for example, reports mean and median household income separately.
The incomes in the demo are invented for illustration.