What is it?

Sampling is a means by which a small group of items (the sample), are taken from a larger group (the population), so as to be representative of the larger group.

When to use it

  • Gathering data
  • Analysing data
  • Implementing and testing solutions
  • Ensuring continuous improvement

What does it achieve?

Careful sampling enables inferences to be made about the whole population, using the results obtained from the sample. The precision of results derived from the sample can be judged.

Most large groups (populations) from which data are required are far too large to take information from each individual item. However, a small group (sample), if designed carefully, can represent the total population.

Inferences can be drawn about the population from the data obtained from the sample.

Key steps

  • Identify the population
  • Choose a sample size
  • Determine sampling technique
    • Simple random sample
    • Stratified sampling (layer)
    • Cluster sampling (group)
    • Systemic sampling (systematic, every third unit etc.)
    • Quota sampling (proportional share)