Sampling methods

• What is opportunity sampling?

  Participants are recruited conveniently at the right time when the study is being carried out
• What is a strength of opportunity sampling?


  It is an easy method of recruitment

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

  It may lead to unrepresentative samples

  Researcher bias - researcher controls who is selected
• What does random sampling ensure?

  All members have equal chances of selection
• How is random sampling conducted?

  Each individual is assigned a number, random number generator or lottery method is used to select individuals for the sample
• What is a strength of random sampling?

  It eliminates researcher bias
• What is a weakness of random sampling?

  It can be time-consuming
• What is volunteer bias?

  When participants refuse to take part so results in an unrepresentative sample

  weakness of random sampling
• What is stratified sampling?

  Sampling based on proportions of subgroups
• What is a strength of stratified sampling?

  no researcher bias

  provides representative data so can be generalised to population
• What is a weakness of stratified sampling?

  It can be time-consuming to calculate proportions

  cannot reflect differences between people in the wider population
• What is systematic sampling?

  Selecting every nth member from a list
• What is a strength of systematic sampling?

  It usually results in a representative sample

  avoids researcher bias
• What is a weakness of systematic sampling?

  It may not be truly unbiased
• How does self-selection affect sampling?

  It can lead to volunteer bias in results
• What motivation might drive participants in studies?

  Money could drive participants to take part
• How can motivation affect study results?

  It may lead participants to not take it seriously