Psychological Investigation Revision notes

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  • Created by: myah
  • Created on: 29-12-12 17:35

Self reports:

Self reports can be thought of as a kind of written interview. They can be an effective means of measuring the behaviour, attitudes, preferences, opinions and intentions of relatively large numbers of subjects more cheaply and quickly than other methods.

Advantages of self reports:

·         If respondents are anonymous their answers may be more honest.

·         Reduces interviewer bias.


·         Social desirability-people may respond in ways they think are socially acceptable rather than say what they really think.

·         The sample of people may not be representative of the population so generalisation is risky.

Open ended questions:

Enable the respondent to answer in as much detail as he/she likes in her own words.


·         Produce in depth responses relating to what the participant actually thinks rather than being restricted by categories


·         Can be difficult to analyse.

Closed questions:

Require the respondent to choose from a number of pre set alternatives.


·         Easy to score and analyse.


·         Restricted range of answers available (e.g. may force respondent to choose between ‘yes’ or ‘no’ when they may wish to answer ‘sometimes’)

·         With ‘yes/’no’ answers may be prone to acquiescence response set (ARS) always responding with a ‘yes’ –it is easier to do this tan say no as they may be asked why.

Sampling methods

Opportunity sample

People who are available at the time of study, fit criteria and are willing to take part.

Disadvantages-it is not representative and biased. You will have a certain type of participant-those who are there at the time.

Advantages-it allows a larger quantity of sampling much more easily and quickly. It is convenient as it takes very little time.

Random sample

Every person in the target population has an equal chance of being selected to take part.

Disadvantages-it is time consuming and can be expensive. Also when you identify participants they may not always want to take part.

Advantages-it is unbiased as all members of the target population have an equal chance of taking part.

Volunteer or self selected sample

This is where the participants volunteer to take part in response to an advertisement, e-mail or a leaflet. Maybe monetary incentive.

Disadvantages- biased and not representative because only a certain type of person volunteers to take part in a study. Also can be expensive to advertise and time consuming to test that volunteers are suitable.

Advantages-can generate a wide variety of participants sometimes. Also people who volunteer are less likely to drop out.


Refers to the consistency of the questionnaire, (do you get the same results every time).Internal reliability refers to how consistent the actual questionnaire is within itself. Usually measured by checking weather people tend to answer each item in the same way as they answer all the others. Checking for ARS. External reliability looks at whether the test produces similar results on different occasions. This can be measured by…


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