Describe why psychologists operationally define the independent variable and the dependent variable in experiments, using any examples.

Mark scheme

Marking points from the official mark scheme (Feb/Mar 2019). The mark or mark type is shown in brackets.

1. [6] 1 mark per descriptive point about operationalisation in general or in relation to the IV and DV 1 mark per example (from a study or made up) that is linked to operationalisation, up to a maximum of 4. For maximum marks, there must be at least one descriptive point about the IV and one descriptive point about the DV and at least two examples (of either/both). operationalisation helps to make replication possible = 1 (description) e.g. Baron-Cohen et al. identified AS/HFAs and normals by whether or not they had a diagnosis (IV) = 1 (example) operationalisation of the IV is about making the way the experimental (and control) conditions have been manipulated/set up clear = 1 (description) e.g. Bandura defined the IV of gender as 'boys' and 'girls' = 1 (example) operationalisation of the DV is about making clear the way the effect of the IV is measured = 1 (description) e.g. Andrade counted the number of names / places remembered = 1 (example) and improves reliability / allows all researchers to measure the DV in a consistent way = 1 (description) e.g. Bandura had a checklist of behaviours for observers to record = 1 (example)