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Thinking back to your research process, one of the things that researchers have to decide on during stage 4: (design study) is how to recruit participants. In psychology research we call this the SAMLING method.
You can find information on the different sampling methods, as well as evaluation points in your handout (on the 'methods' page)
what is a sample?
what is a sample?
The word 'sample' doesn't change meaning just because we're talking about psychology , it's "a small part or quantity intended to show what the whole is like". So in the context of psychological research, it's the group of people we select to 'test'...
Why? Because testing our target population is usually IMPRACTICAL. Imagine researching UK adults... that's around 50 million people. How would you test them all? Apart from the census and referendums like elections, testing everyone is usually out of the question.
When you sample paint, you don't paint the entire room... you test a small section to get an idea of how the whole room would look... In psychology we test a small group and, based on our findings, make assumptions about the whole target population
KEY TERMS
KEY TERMS
Sampling is the process of selecting a representative group from the population under study.
The target population is the total group of individuals from which the sample might be drawn.
A sample is the group of people who take part in the investigation. The people who take part are referred to as “participants”.
Generalisability / representativeness refers to the extent to which we can apply the findings of our research to the target population we are interested in.
As always, Mr Martin Explains has a great video on populations and samples. Have a watch and note down the main types of sampling he mentions - leave space to add notes as you'll need to know about EACH of these types!
why is it important?
why is it important?
Think about why it's important to have a representative sample. What would happen to the findings of our research if our sample was non-representative / couldn't be generalised to the wider target population?
Imagine a scenario in which a researcher is seeking to investigate the effect of different substances on hand-eye co-ordination in a whack-a-mole task. It's not the most 'psychology' example but it'll work for what we need. After choosing the topic, reviewing the literature and formulating a hypothesis the researcher turns to designing the study and deciding on an appropriate sample (who to test) and sampling method (how to recruit them)
your sample matters
your sample matters
After carefully thinking through and planning the practical elements of the study, the researcher goes to a local boxing club to ask for volunteers to take part in the study.
think about it / write it down...
think about it / write it down...
How might using a sample of amateur boxes be problematic for the research?
How would this sample compare with the general population?
What does this do the reliability of the findings of the research?
ACTIVITY...
ACTIVITY...
Provide a definition for the terms 'sample', 'sampling', 'representative', 'biased'/'unbiased' and ' target population'.
Use the above words in 1 or 2 sentences to describe the goal / importance of proper sampling
SAMPLING METHODS
SAMPLING METHODS
Luckily for us, researchers before us have come up with a variety of SAMPLING METHODS used by psychologists when recruiting their samples. Each of these SAMPLING METHODS has its own strengths and weaknesses.
YOU NEED TO BE ABLE TO name and describe sampling methods from a given scenario and be able to suggest which sampling methods might be appropriate for a given research scenario.
ACTIVITY...
ACTIVITY...
Provide a definition for the terms 'sample', 'sampling', 'representative', 'biased'/'unbiased' and ' target population'.
Use the above words in 1 or 2 sentences to describe the goal / importance of proper sampling
WE'RE GOING TO LOOK AT THREE OF THE MOST COMMON SAMPLING METHODS USED BY PSYCHOLOGY RESEARCHERS... MAKE THESE PAGE / SECTION HEADINGS AND TAKE NOTES FOR EACH...
WE'RE GOING TO LOOK AT THREE OF THE MOST COMMON SAMPLING METHODS USED BY PSYCHOLOGY RESEARCHERS... MAKE THESE PAGE / SECTION HEADINGS AND TAKE NOTES FOR EACH...
OPPORTUNITY - RANDOM - SELF-SELECTED
OPPORTUNITY - RANDOM - SELF-SELECTED
OPPORTUNITY SAMPLING
OPPORTUNITY SAMPLING
Depending on where you are conducting your research, it might simply be a case of asking those around you to take part! It's a really quick and easy way to get participants BUT it's vulnerable to biases. Consider, students often use this method for psychology research at college / university ... are students representative of the general population?
RANDOM SAMPLING
RANDOM SAMPLING
Short of testing your entire target population, random-sampling is one of the best ways to get a representative sample. On the downside, it's more involved than opportunity sampling - you first have to identify your target population and get info on them all. Not only that, the randomly-selected people you invite to take part might say no!
SELF-SELECTED SAMPLING
SELF-SELECTED SAMPLING
A quick google search and you'll find thousands of opportunities to volunteer to take part in research. It might seem similar to opportunity sampling (asking those around you) but in self-selected sampling, potential participants respond to an advert (it might be online or in college you might see posters up asking for volunteers).
Self-selected sampling removes some of the potential for researcher bias that goes along with an opportunity sample (for example, a researcher using an opportunity sampling method might only ask people they find 'approachable' and avoid anyone they don't like the look of). However, it's not perfect. For example, thinking about confidence / self-esteem, what type of people might be likely to volunteer to take part in research?
activities (complete on G classroom, research 4)
activities (complete on G classroom, research 4)
Name and describe three different sampling methods psychology researchers might use to recruit participants
For each of the following scenarios, state which sampling method the researcher has used AND why you have chosen your answer (0 marks will be awarded for identifying it ONLY).
A researcher wants to test the effect of different teaching methods on learning; they put up posters in and around their college to recruit participants. Volunteers respond to the appeal for participants by emailing the researcher
A researcher wants to investigate if there is an effect of religion on resilience. They access the (made up) database of registered Wiccans and use a random number generator to pick out potential participants who are then emailed to see if they would like to take part.
A researcher is seeking to study the effect of techno music on mood. They go to a music festival and hang about outside the 'techno-tent' asking anyone who comes out of the tent if they could take part.
Additional resources:
https://www.thh.nhs.uk/documents/_Departments/Research/InfoSheets/16_sampling_research.pdf
The linked PDF is from The Hillingdon Hospital NHS group - it’s their guidelines for selecting a good sample and covers the purpose of sampling, sampling errors and types of sampling
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