• Systematic sampling is a probability sampling method in which a random sample at a fixed periodic interval is taken from a larger population.

  • A fixed periodic interval, called the sampling interval, is calculated by dividing the population size by the desired sample size.
  • The advantages of this methodology include the elimination of the phenomenon of cluster selection and the low possibility of data contamination.
  • Disadvantages include over- or under-representation of certain patterns and greater risk of data manipulation.
  • There are three main types of systematic samples: random systematic samples, linear systematic samples and circular systematic samples.