'Counting pills is the only valid way to measure adherence to medical advice.' To what extent do you agree with this statement? Use examples of research you have studied to support your answer.

Mark scheme

Marking points from the official mark scheme (Feb/Mar 2018). The mark or mark type is shown in brackets.

1. Marks: use generic levels of response in table C.
2. Syllabus: Measuring non-adherence: objective: pill counting (Chung and Naya, 2000)
3. Most likely (any other appropriate responses should be credited):
4. For: Pill counting is an objective measure resulting in quantitative data.
5. Many studies have used pill counts: Chung and Naya (TrackCap).
6. Pill counts cannot be manipulated by the user: use recorded every time pill has left container.
7. Measure has face validity.
8. Said to be more accurate than asking user whether medicine has been taken.
9. Against: Measure is not valid: just because pill has left container, doesn't mean it has been taken.
10. Trackcap has flaws: 'The device was programmed to recognise, but not accumulate, multiple openings that occurred within 1 min of each other. If the cap was left off for 15 min or more, the device recorded one additional event.' (Chung and Naya, 2000).
11. Valid: biochemical tests (e.g. Roth and Caron, 1978); possibly repeat prescriptions (Sherman et al., 2000)