| Date | May 2019 | Marks available | 22 | Reference code | 19M.Paper 2.BP.TZ0.1 |
| Level | SL and HL | Paper | Paper 2 | Time zone | TZ0 |
| Command term | Discuss | Question number | 1 | Adapted from | N/A |
Question
Discuss validity and reliability of diagnosis.
Markscheme
Refer to the paper 2 assessment criteria when awarding marks. These can be found under the “Your tests” tab > supplemental materials.
The command term “discuss” requires candidates to offer a considered review that addresses various aspects of validity and reliability of diagnosis. Although a discussion of both validity and reliability is required, it does not have to be evenly balanced to gain high marks.
Relevant classification systems in the discussion of validity and reliability of diagnosis include, but are not limited to:
- Diagnostic Statistical Manual (DSM)
- Chinese Classification of Mental Disorders (CCMD)
- International Classification of Diseases (ICD).
Examples of research that could be used include, but are not limited to:
- Nicholls et al.’s (2000) studies of inter-rater reliability
- Seeman’s (2007) literature review on the reliability of diagnosis
- Wakefield et al.’s (2007) study on the validity of diagnosis
- Silverman et al.’s (2001) study on test-retest of anxiety symptoms and diagnosis
- Rosenhan’s studies of diagnostic validity.
If a candidate discusses only validity or only reliability, the response should be awarded up to a maximum of [3] for criterion B: knowledge and understanding. All remaining criteria should be awarded marks according to the markbands independently, and could achieve up to full marks.
Examiners report
This was a very popular question. In the majority of cases it was not well answered – candidates tended to provide simple definitions of validity and reliability and then focus on description of research studies (most popular Rosenhan’s study on validity and Cooper’s study on reliability). Descriptions of these studies were rather basic and often inaccurate. The evaluation was also oversimplified and evidence of critical thinking was often not relevant to the question. Sometimes only reliability or validity was addressed or the candidate failed to discuss what the focus of the question was and randomly used validity or reliability in the response. Stronger candidates did a good job of differentiating between validity and reliability, as well as supporting their argument with relevant research studies. References were often made to the following studies: Li-Repac (1980) and Lipton and Simon (1985).
