Sampling

• What is opportunity sampling?

  It consists of taking the sample from people who are available at the time the study is carried out and fits the criteria you are looking for 
• What are the strengths of opportunity sampling?

  • Quick
  • Cheap
  • Easy
  • Time-efficient
• What are the weaknesses of opportunity sampling?

  Not necessarily representative due to chance and is open to accidental researcher bias 
• What is random sampling?

  Ensures each member of the target population has the same chance of being selected as any other member. This could be done by drawing names from a hat. 
• What are the strengths of random sampling?

  Every member has an equal chance of being chosen
• What are the weaknesses of random sampling?

  • Can be highly time consuming if sample size is large 
  • Not everyone picked may consent to taking part, raises ethical issues 
• What is self selected sampling?

  Participants become part of the study as they volunteer themselves through response to recruitment offers often through adverts or emails 
• What are the strengths of self-selected sampling?

  • Volunteers are more likely to commit to the study and be fully involved in the study therefore less likely to drop out 
  • Can gain a large sample quickly that reaches a broad and representative audience 
• What are the weaknesses of self-selected sampling?

  • Participants are more prone to demand characteristics and social desirability 
  • There may be inherent bias in the participants, as they may sign up due to interest/need for money/need experience doing studies 

   

   
• What is stratified sampling?

  Involves classifying the population into categories and then choosing a sample which consists of participants from each category in the same proportions they are in the population 
• What are the strengths of stratified sampling?

  Sample will be representative and has no biases 
• What are the weaknesses of stratified sampling?

  Method is difficult, costly and time inefficient. Means the target population must be fully accessible 
• What is snowball sampling?

  Involves getting participants to find others like them, so the sample slowly grows 
• What are the strengths of snowball sampling?

  Allows you to access people that may not otherwise be able to recruit 
• What are the weaknesses of snowball sampling?

  • It can have bias meaning the sample is not representative of a wide enough group of people 
  • Can be time-consuming