Sampling

• What is opportunity sampling?

  Participants that happen to be available at the time of the study being carried out
• What is a strength of opportunity sampling?

  Time saving and less costly
• What is a limitation of opportunity sampling?

  • Not representative of the whole population so lacks generalisability
  • Researcher bias is presented as they control who they want to select
• What is random sampling?

  Participants have an equal chance of being the one that is selected.
• What is a strength of random sampling?

  No researcher bias as researcher has no influence in who is being picked
• What is a limitation of random sampling?

  • Time consuming
  • Volunteer bias- participants can refuse to take part so can end up with unrepresentative samples
• What is systematic sampling?

  Every nth person is selected from the sampling frame
• What is a strength of systematic sampling?

  Avoids researcher bias and usually fairly representative of population
• What is a limitation of systematic sampling?

  Not truly unbiased unless you use a random number generator and then start the systematic sample
• What is stratified sampling?

  Reflects the varying proportions of people in particular subgroups (strata) within the wider population
• What is a strength of stratified sampling?

  • No researcher bias
  • Produced representative data due to the proportional strata
• What is a limitation of stratified sampling?

  • Time consuming
  • Identified strata cannot reflect all differences between the people of the wider population
• What is volunteer sampling?

  Self selection whereby the participant offers to take part
• What is a strength of volunteer sampling?

  • Easy and not time consuming
  • Participants are more likely to cooperate in the study
• What is a limitation of volunteer sampling?

  • Volunteer bias- study may attract a particular profile of a person
  • Motivations like money
  • May not take study seriously
• What is time sampling?

  The recording of behaviour within a timeframe that is pre-established before the observational study
• What is event sampling?

  Involves the counting of the number of times a particular behaviour is carried out by the target group or individual you are watching