Table 4 Reference table for the number of test iterations to obtain a \(\rho (\phi )\) of 50% as a function of sensitivity a, specificity b and disease prevalence \(\phi\)
From: Bayesian updating and sequential testing: overcoming inferential limitations of screening tests
\(\ln \left(\frac{a}{1-b}\right)\) | Prevalence \((\phi )\) | |||||
|---|---|---|---|---|---|---|
0.02 | 0.05 | 0.07 | 0.1 | 0.15 | 0.2 | |
0.50 | 7.78 | 5.89 | 5.17 | 4.39 | 3.47 | 2.77 |
1.00 | 3.89 | 2.94 | 2.59 | 2.20 | 1.73 | 1.39 |
1.50 | 2.59 | 1.96 | 1.72 | 1.46 | 1.16 | 0.92 |
2.00 | 1.95 | 1.47 | 1.29 | 1.10 | 0.87 | 0.69 |
2.50 | 1.56 | 1.18 | 1.03 | 0.88 | 0.69 | 0.55 |
3.00 | 1.30 | 0.98 | 0.86 | 0.73 | 0.58 | 0.46 |
3.50 | 1.11 | 0.84 | 0.74 | 0.63 | 0.50 | 0.40 |
4.00 | 0.97 | 0.74 | 0.65 | 0.55 | 0.43 | 0.35 |
4.50 | 0.86 | 0.65 | 0.57 | 0.49 | 0.39 | 0.31 |
5.00 | 0.78 | 0.59 | 0.52 | 0.44 | 0.35 | 0.28 |