**Clinical factors** |

Probability of mastoiditis—WW/DP | 0.000019 | 0.000 | 0.000038 | 1, 34 |

Probability of mastoiditis—routine amoxicillin | 0.000010 | 0.000 | 0.000020 | 1, 34 |

Probability of nonattendance—WW | 0.203 | 0.173 | 0.233 | 35 |

Probability of nonattendance—DP | 0.37 | 0.292 | 0.448 | 23 |

Probability of nonattendance—routine amoxicillin | 0.06 | 0.044 | 0.076 | 27 |

Probability of clinical failure with nonattendance—any strategy | 0.077 | 0.053 | 0.101 | 28 |

Probability of clinical failure; prescription for amoxicillin redeemed—DP | 0.24 | 0.172 | 0.308 | 21 |

Probability of clinical failure—WW | 0.175 | 0.147 | 0.203 | 27 |

Probability of clinical failure—routine amoxicillin | 0.061 | 0.044 | 0.078 | 28 |

Probability of GI adverse effects | 0.099 | 0.042 | 0.156 | 21, 30, 31 |

Probability of dermatologic adverse effects | 0.02 | 0.000 | 0.04 | 32 |

**Costs, $** |

Amoxicillin | 9.40 | 7.74 | 14.95 | 36 |

Amoxicillin-clavulanate | 47.80 | 31.22 | 71.70 | 36 |

Hospitalization for mastoiditis | 5,340.00 | 2,670.00 | 10,680.00 | 33 |

Home IV antibiotics for mastoiditis (includes home nurse visits) | 305.00 | 178.00 | 545.00 | 36, 37 |

Office consultation | 34.23 | 17.12 | 68.46 | 37, 38 |

Non–health care | 15.08 | 7.54 | 30.16 | 39 |

Work loss | 91.00 | 46.00 | 182.00 | 39 |

**Utilities** |

Day of AOM | 0.79 | 0.713 | 0.867 | 40 |

Day of treatment success | 0.96 | 0.942 | 0.978 | 40 |

Day of treatment failure | 0.72 | 0.646 | 0.794 | 40 |

GI adverse effects from antibiotics | 0.70 | 0.608 | 0.792 | 40 |

Rash from antibiotics | 0.77 | 0.694 | 0.846 | 40 |