We want our research to apply to as many people as possible. We want to discover truths about all humans, not just a handful of people we research on.
Key Terms
Samples can be biased; they do not reflect the target population and this affects the conclusions we can draw from these samples.
Therefore, we need to be careful in selecting participants for our study. There are four different sampling techniques we use to do this.
Opportunity Sampling
Anyone who is available at the time of your research.
e.g. I want to research into the eating habits of men. I walk around the college and survey the first 20 males I find.
Evaluation
Self-selected Sampling (volunteer)
Participants choose themselves to take part in the study. They could be recruited through; using online email surveys, signing up or applying to take part, or responding to adverts or posters.
e.g. Who would fill out an online survey?
Evaluation
Snowball Sampling
Participants are recruited through being friends/colleagues of existing participants.
e.g. The researcher may know five participants to take part in their research but needs more, so may ask the participants themselves to bring friends of theirs to take part in the research too.
Evaluation
Random sampling
Every member of the population has a fair and equal chance of taking part.
e.g. Everybody puts their name into a hat, draw first 25 names out of the hat for the sample.
Facebook (2012): Randomly chose 689,000 users and showed either more positive or more negative wall posts.
Evaluation
Key Terms
- Target Population: The set of people researchers want to find out about.
- Sample: A small set of people taken from the target population.
- Representative: How well a sample reflects the target population.
- Gender bias: Sample is made of people from one gender, it is not representative of all genders.
- Androcentric: biased towards men.
- Estrocentric: biased to women.
- Cultural bias: Sample is too focused on one culture, isn’t representative of all cultures.
- Ethnocentric: biased towards one culture/ethnicity
- Population validity: Can we generalise results from our sample to the target population?
Samples can be biased; they do not reflect the target population and this affects the conclusions we can draw from these samples.
Therefore, we need to be careful in selecting participants for our study. There are four different sampling techniques we use to do this.
Opportunity Sampling
Anyone who is available at the time of your research.
e.g. I want to research into the eating habits of men. I walk around the college and survey the first 20 males I find.
Evaluation
- Quick and cheap to carry out, so easy to replicate.
- Good for characteristics that we can assume are the same for everyone.
- Only sampling method for some research methods (covert field experiment).
- Sample Bias (researcher might choose helpful looking people).
- Still have to ask the participant to take part, which means they could decline.
Self-selected Sampling (volunteer)
Participants choose themselves to take part in the study. They could be recruited through; using online email surveys, signing up or applying to take part, or responding to adverts or posters.
e.g. Who would fill out an online survey?
Evaluation
- Quick and practical to carry out, so easy to replicate.
- Can reach a wider variety of participants.
- Ethical, as participants have given their consent to taking part.
- Sample Bias (biased towards the type of person who volunteers for research).
Snowball Sampling
Participants are recruited through being friends/colleagues of existing participants.
e.g. The researcher may know five participants to take part in their research but needs more, so may ask the participants themselves to bring friends of theirs to take part in the research too.
Evaluation
- Quick and practical to carry out, so easy to replicate.
- Can reach a wider variety of participants.
- Ethical, as participants have given their consent to taking part.
- Sample Bias (probably similar culture as all friends).
Random sampling
Every member of the population has a fair and equal chance of taking part.
e.g. Everybody puts their name into a hat, draw first 25 names out of the hat for the sample.
Facebook (2012): Randomly chose 689,000 users and showed either more positive or more negative wall posts.
Evaluation
- The most representative sampling technique to use.
- Provides unbiased sample.
- Time consuming and often impossible.
- Still have to ask the participant to take part, which means they could decline
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