# Inference for effect ratio

### Description

Conducts inference on effect ratio as described in Section 3.3 of Baiocchi (2010), resulting in an estimate and a permutation based confidence interval for the effect ratio.

### Usage

1 |

### Arguments

`dta` |
Data frame where first column is outcome and second column is treatment |

`match` |
Data frame where first column contains indices for those individuals encouraged into treatment by instrumental variable and second column contains indices for those individuals discouraged from treatment by instrumental variable |

`alpha` |
Level of confidence interval |

### Value

`est.emp` |
Empirical estimate of effect ratio |

`est.HL` |
Hodges-Lehmann type estimate of effect ratio |

`lower` |
Lower limit to 1-alpha/2 confidence interval for effect ratio |

`upper` |
Upper limit to 1-alpha/2 confidence interval for effect ratio |

### Author(s)

Joseph Rigdon jrigdon@stanford.edu

### References

Baiocchi M, Small D, Lorch S, Rosenbaum P (2010). Building a stronger instrument in an observational study of perinatal care for premature infants. Journal of the American Statistical Association, 105(492), 1285-1296.

### See Also

`eff.ratio`