reliability

• reliability is a measure of consistency. If a particular measurement is repeated and the same result is obtained then that measurement is described as being reliable
• the 2 ways of assessing reliability are:

  • test-retest
  • inter-observer
• test-retest is the same test or questionnaire is given to the same person on 2 or more different occasions. If the test of questionnaire is reliable the results should be the same (or very similar) each time it is administered
• inter-observer is in an observation, 2 or more observers compare their data by conducting a pilot study (a small-scale trial run of the observation to check that observers are applying behavioural categories in the same way). Observers should watch the same event or the sequence of events but record their data separately
• the 4 ways of improving reliability are:

  • questionnaires
  • observations
  • experiments
  • interviews
• a questionnaire can improve reliability by replacing the number of open questions with closed questions
• interviews improve reliability by using the same interviewer each time. If this isn't possible, all interviewers must be trained like so so they avoid questions that are leading or ambiguous
• observations improve reliability by making sure that all behavioural categories are operationalised and measurable. Categories shouldn't overlap and all possible behaviours should be included. If categories are overlapping or absent, different observers have to use their own judgement in deciding what to record and where
• experiments improve reliability by making sure that the procedures are the same every time. This is so that performance of different particitpants can be compared