Mean: what it means
The total of all values divided by how many there are. Often what people mean by 'average', it can be pulled up or down by a few extreme values.
The mean (or arithmetic mean) is the sum of all values divided by the number of values. It uses every value, which makes it useful for totals and budgets, but it is sensitive to extremes.
Worked example
Ten hypothetical households: nine have an income of £30,000 and one has £330,000. The total is £600,000, so the mean is £60,000. The median is £30,000. Adding one very high income doubled the mean but left the median unchanged.
When the mean is the right tool
- If you want to know total spending or total tax, mean values multiplied by counts give the total. A median cannot do that.
- ONS average weekly earnings is a mean-based measure, which is why it reacts to bonuses and high earners.
How it trips up claims
- "The average family" built from a mean income may describe very few real families when incomes are spread unevenly.
- Comparing a mean from one source with a median from another mixes measures.
- When incomes at the top rise faster, the mean can rise while the median stays flat.
Also searched as: arithmetic mean, average, mean vs median, mean average
Official figures that use this term
Read live from the publishers.
Key figures where it matters
- UK average weekly earnings growth
- UK average house price
- UK average private rent
- Average weekly hours worked in the UK
- Life expectancy at birth (UK)
- Average quoted 2-year fixed mortgage rate
- Average UK petrol and diesel price
Questions that use this term
- What is the average salary in the UK?
- What is the median household income in the UK?
- What is the Gini coefficient for the UK?
Related terms
- Median: The middle value when all values are ordered from lowest to highest. Half are above and half below, so a few very large values cannot pull it up.
- Per capita (per head): A total divided by the number of people in the population, such as GDP per head or spending per person, to allow fair comparison between places or years.
More averages, rates and risk terms: Median · Per capita (per head) · Rate per 100,000 · Crude rate · Age-standardised rate · Odds, risk, relative and absolute risk · Deciles and quintiles · Weighted average.