reliability Flashcards
what is reliability?
refers to the consistency of findings from an investigation or measuring tool
what is test-retest reliability?
● method of assessing the reliability of a questionnaire or psychological test (can also be used for interviews)
● the same person is assessed on two separate occasions
● two sets of scores are correlated to make sure they are similar
● shows to what extent the test produces the same answers (is consistent / reliable)
● if correlation is significant (and positive) then the reliability of measuring instrument assumed to be good
what is inter-observer reliability?
● extent to which there is agreement between 2 or more observers involved in observation of behaviour
● check that observers are applying behavioural categories in the same way
● if correlation between observers is +80 then data has high inter-observer reliability
how to improve reliability in a questionnaire?
● a questionnaire that produces low test-retest reliability may need some questions deselected / rewritten
● researcher may replace some open questions (which could be interpreted inconsistently) with closed questions that are less ambiguous
how to improve reliability in interviews?
● to ensure reliability - use same interviewer
● if this is not possible, all interviewers must be trained so they ask same questions in the same way
how to improve reliability in observations?
● behavioural categories should be operationalised and measurable, so they are less open to interpretation
● if this does not happen, different observers have to use their own judgement in deciding what to report and may end up with inconsistent results
how to improve reliability in experiments?
● to compare the performance of different participants, the procedure must be the same each time
● therefore, standardised procedure should be used
