Schulz Philipp, Wegwarth Odette, Giese Helge
Heisenberg Chair for Medical Risk Literacy & Evidence-Based Decisions, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany.
Max Planck Institute for Human Development, Berlin, Germany.
BMC Med Educ. 2025 Apr 9;25(1):505. doi: 10.1186/s12909-025-06990-6.
To make reasonable future medical decisions, medical students need to be sufficiently educated to interpret diagnostic tests. Natural frequencies are considered the gold standard for understanding single diagnostic test results. However, they may be less suitable in situations involving sequential diagnostic testing. We test whether odds and likelihood ratios (odds/LR) may serve as a viable alternative in these situations.
In our preregistered randomized-controlled crossover trial, we recruited 167 medical students and 162 psychology students. The proportion of correctly calculated positive predictive values of a single (PPV) and two sequential diagnostic tests (sPPV) was the primary, the subjective comprehensibility of the information the secondary outcome.
The proportion of correct PPVs was significantly higher in the natural frequency (36.2%) compared to the odds/LR format (21.6%), OR 2.41. Conversely, the proportion of correct sPPVs was significantly higher in the odds/LR (10.6%) compared to the natural frequency format (4.9%), OR 2.73. Participants indicated a higher subjective comprehension of test statistics phrased as natural frequencies (Mdn = 19) than as odds/LR (Mdn = -15), r = .61.
Teaching Odds/LR next to natural frequencies potentially improves medical students' understanding of PPV and may enhance their ability to make future diagnostic decisions.
为了做出合理的未来医疗决策，医学生需要接受足够的教育以解读诊断测试结果。自然频率被认为是理解单一诊断测试结果的黄金标准。然而，在涉及连续诊断测试的情况下，它们可能不太适用。我们测试在这些情况下，比值比和似然比（odds/LR）是否可以作为一种可行的替代方法。
在我们预先注册的随机对照交叉试验中，我们招募了167名医学生和162名心理学学生。单一诊断测试（PPV）和两项连续诊断测试（sPPV）的正确计算的阳性预测值的比例是主要结果，信息的主观可理解性是次要结果。
与比值比/似然比格式（21.6%）相比，自然频率格式下正确PPV的比例显著更高（36.2%），比值比为2.41。相反，与自然频率格式（4.9%）相比，比值比/似然比格式下正确sPPV的比例显著更高（10.6%），比值比为2.73。参与者表示，与以比值比/似然比表述（中位数=-15）相比，以自然频率表述的测试统计数据的主观理解更高（中位数=19），相关系数r=0.61。
除自然频率外，教授比值比/似然比可能会提高医学生对PPV的理解，并可能增强他们未来做出诊断决策的能力。
