Sensitivity — MRCPsych Paper A MCQ
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Correct answer: D — High sensitivity
The correct answer is D, high sensitivity. Sensitivity is the proportion of people with the target condition who test positive: TP/(TP + FN). A highly sensitive screening questionnaire therefore produces few false-negative results and misses few genuine cases. Lowering the threshold commonly increases sensitivity at the cost of reduced specificity and more false positives. High specificity instead means correctly identifying people without alcohol misuse and generating few false positives. Positive predictive value is the proportion of positive results that are true positives; accepting more false positives may reduce it, and it also depends on prevalence. Inter-rater reliability concerns agreement between assessors, while face validity concerns whether the questionnaire appears to measure alcohol misuse.
Reference: Florkowski CM. Sensitivity, specificity, receiver-operating characteristic (ROC) curves and likelihood ratios: communicating the performance of diagnostic tests. Clinical Biochemist Reviews. 2008;29(Suppl 1):S83-S87. https://pubmed.ncbi.nlm.nih.gov/18852864/