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%.