Survey sample: what it means

The group of people or businesses selected to take part in a survey, chosen so that their answers can be used to estimate figures for the whole population.

A survey sample is the subset of a population that is selected and asked to take part. Results are weighted (grossed up) so that they represent the whole population. The Labour Force Survey and the Crime Survey for England and Wales are examples.

Worked example

If a hypothetical survey interviews 10,000 people from a population of 50 million, each respondent represents on average 5,000 people. If 400 report being unemployed, the estimate is about 2 million. Weighting adjusts this so that, for example, age and region match known population totals.

Sampling error

A different random sample would give a slightly different answer. This sampling variability is why survey estimates come with confidence intervals. Larger samples give narrower intervals, but small subgroups, such as one region or age band, have fewer respondents and wider uncertainty.

How it trips up claims

• A small monthly change in a survey estimate can be within sampling variability; check whether it is statistically significant.
• If certain groups do not respond, the sample may not represent them well even after weighting (see response rate).

Also searched as: sample survey, sample size, sampling error, survey weighting

Official definitions: ONS: Labour Force Survey user guidance · ONS: Uncertainty and how we measure it · ONS: Crime in England and Wales, latest bulletin

Key figures where it matters

• UK economic inactivity rate
• UK employment rate
• UK unemployment rate
• Average weekly hours worked in the UK
• Crime Survey for England and Wales: headline crime
• UK redundancy rate
• Number of self-employed people in the UK

Questions that use this term

• How is UK unemployment calculated?
• Is crime going up or down in the UK?
• Is the Office for National Statistics reliable?

Related terms

• Response rate: The share of people or businesses selected for a survey who actually take part. Lower response rates can make estimates less precise and risk bias.
• Confidence interval: A range around an estimate that shows how much it could vary because it comes from a sample. A 95% interval is the usual standard.
• Statistical significance: A test of whether a difference between estimates is larger than would be expected from sampling variation alone. It does not mean the difference is large or important.
• Administrative data: Information collected by organisations while running a service, such as tax records, benefit claims or hospital activity, and then used to produce statistics.

More statistics, surveys and quality terms: Accredited official statistics · Official statistics in development · Pre-release access · Response rate · Administrative data · Provisional figures · Revisions · Confidence interval · Statistical significance · Headline figure · Sample size · Labour Force Survey (LFS).