# Balance Measures

### Description

Balance assessment for individual variables, before and after matching

### Usage

1 2 3 4 5 6 7 8 | ```
sdiff(varname, treatment, orig.data, match.data = NULL,
treat.wts = NULL, ctrl.wts = NULL, mt.wts = NULL, mc.wts = NULL)
ttest.balance(varname, treatment, orig.data, match.data = NULL,
treat.wts = NULL, ctrl.wts = NULL, mt.wts = NULL, mc.wts = NULL)
fisher.balance(varname, treatment, orig.data, match.data = NULL,
treat.wts = NULL, ctrl.wts = NULL, mt.wts = NULL, mc.wts = NULL)
wilc.balance(varname, treatment, orig.data, match.data = NULL,
treat.wts = NULL, ctrl.wts = NULL, mt.wts = NULL, mc.wts = NULL)
``` |

### Arguments

`varname` |
name of the variable on which to test balance |

`treatment` |
name of the binary indicator for treatment status |

`orig.data` |
a data frame containing the data before matching |

`match.data` |
an optional data frame containing the matched sample |

`treat.wts` |
optional weights for treated units in the original sample |

`ctrl.wts` |
optional weights for control units in the original sample |

`mt.wts` |
optional weights for treated units in the matched sample |

`mc.wts` |
optional weights for treated units in the matched sample |

### Details

The `sdiff`

function computes the standardized difference in means. The other functions perform different kinds of balance tests: `t.balance`

does the 2-sample t-test, `fisher.balance`

does Fisher's exact test for binary variable, and `wilc.balance`

does Wilcoxon's signed rank test.

### Value

a labeled vector. For `sdiff`

, the vector has six elements if `match.data`

is provided: treated and control means and standardized differences before and after matching. If `match.data`

is not provided, the vector has only the three elements corresponding to the pre-match case.

For the other functions, if `match.data`

is provided, the vector contains p-values for the test before and after matching. Otherwise a single p-value is given for the pre-match data.

### Author(s)

Luke Keele, Penn State University, ljk20@psu.edu

Sam Pimentel, University of Pennsylvania, spi@wharton.upenn.edu

### References

Rosenbaum, Paul R. (2002). *Observational Studies*.
Springer-Verlag.

Rosenbaum, Paul R. (2010). *Design of Observational Studies*.
Springer-Verlag.

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