Describe reliability and validity, using any examples.

Mark scheme

Marking points from the official mark scheme (Oct/Nov 2021). The mark or mark type is shown in brackets.

1. [6] 1 mark for each definition/detail, up to a maximum of 4, for each issue. 1 mark for each example that is linked to one issue, up to a maximum of 2, for each issue. Examples can include examples from any studies (core studies, other studies, candidate's own studies). Reliability: is the consistency of a procedure, task or measure; (definition) i.e. whether it produces the same results with the same people each time it is used; (definition) (Different types of reliability e.g.) inter-rater reliability which is how similarly two researchers record the same results; And intra-rater reliability, whether one researcher is consistent over time; Test-retest measures the reliability of a test or instrument over time by checking that two tests the same / similar data produce similar results; Split-half measures the reliability of items within a test by looking at whether half the test produces similar results to the other half; Bandura et al.'s study had high reliability because they all used the same scales; Bandura et al.'s observers had a high inter-rater reliability with a coefficient of .89 for the initial testing of aggression / .9 (or more) for the observations; Pepperberg's study had low reliability because the sessions had different lengths of time; Validity: is the extent to which a test or task measures what is claims to measure; (definition) i.e. whether it truly represents reality; (definition) (Different types of validity e.g.) ecological validity which is whether results generalise beyond the setting of the study; Controls/standardisation make experiments more valid; Milgram's study had high validity because the participants believed they were killing someone / showed genuine signs of tension; Milgram's study had low validity because the situation was in a laboratory and it was unlikely that Yale would let people die for an experiment Milgram's study had low validity as electrocuting someone you cannot see is very different from the situation German concentration camp guards were in (and this is what Milgram was trying to test);