| Likelihood Ratio | Approximate Change in Probability (%)* |
| Values between 0 and 1 decrease the probability of disease | |
| 0.1 | −45 |
| 0.2 | −30 |
| 0.3 | −25 |
| 0.4 | −20 |
| 0.5 | −15 |
| 1 | 0 |
| Values greater than 1 increase the probability of disease | |
| 2 | +15 |
| 3 | +20 |
| 4 | +25 |
| 5 | +30 |
| 6 | +35 |
| 7 | |
| 8 | +40 |
| 9 | |
| 10 | +45 |
Easy to recall at the bedside by simply remembering 3 specific LRs—2, 5, and 10—and the first 3 multiples of 15 (i.e., 15, 30, and 45).
An LR of 2 increases probability 15%, one of 5 increases it 30%, and one of 10 increases it 45%. For those LRs between 0 and 1, the clinician simply inverts 2, 5, and 10 (i.e., 1/2 = 0.5, 1/5 = 0.2, 1/10 = 0.1).
Just as the LR of 2.0 increases probability 15%, its inverse, 0.5, decreases probability 15%. Similarly, an LR of 0.2 (the inverse of 5) decreases probability 30%, and a LR of 0.1 (the inverse of 10) decreases it 45%.