R: Balance Statistics for 'sbw' Objects

bal.tab.sbw {cobalt} | R Documentation

## Balance Statistics for `sbw` Objects

### Description

Generates balance statistics for `sbwcau` objects from sbw.

### Usage

    ## S3 method for class 'sbwcau'
    bal.tab(x,
        stats,
        int = FALSE,
        poly = 1,
        distance = NULL,
        addl = NULL,
        data = NULL,
        continuous,
        binary,
        s.d.denom,
        thresholds = NULL,
        weights = NULL,
        cluster = NULL,
        imp = NULL,
        abs = FALSE,
        subset = NULL,
        quick = TRUE,
        ...)

### Arguments

`x` | an `sbwcau` object; the output of a call to `sbw()` from the sbw package.
`stats` | `character`; which statistic(s) should be reported. See `stats` for allowable options. For binary treatments, "mean.diffs" (i.e., mean differences) is the default. Multiple options are allowed.
`int` | `logical` or `numeric`; whether or not to include 2-way interactions of covariates included in `covs` and in `addl`. If `numeric`, will be passed to `poly` as well.
`poly` | `numeric`; the highest polynomial of each continuous covariate to display. For example, if 2, squares of each continuous covariate will be displayed (in addition to the covariate itself); if 3, squares and cubes of each continuous covariate will be displayed, etc. If 1, the default, only the base covariate will be displayed. If `int` is numeric, `poly` will take on the value of `int`.
`distance` | an optional formula or data frame containing distance values (e.g., propensity scores) or a character vector containing their names. If a formula or variable names are specified, `bal.tab()` will look in the argument to `data`, if specified.
`addl` | an optional formula or data frame containing distance values (e.g., propensity scores) or a character vector containing their names. If a formula or variable names are specified, `bal.tab()` will look first in the argument to `data`, if specified, and next in the `sbwcau` object.
`data` | an optional data frame containing variables that might be named in arguments to `distance`, `addl`, `cluster`, and `imp`. Can also be `mids` object, the output of a call to `mice` from the mice package, containing multiply imputed data sets. In this case, `imp` is automatically supplied using the imputation variable created from processing the `mids` object.
`continuous` | whether mean differences for continuous variables should be standardized (`"std"`) or raw (`"raw"`). Default `"std"`. Abbreviations allowed. This option can be set globally using `set.cobalt.options`. This argument is used to set `std` in `col_w_smd`.
`binary` | whether mean differences for binary variables (i.e., difference in proportion) should be standardized (`"std"`) or raw (`"raw"`). Default `"raw"`. Abbreviations allowed. This option can be set globally using `set.cobalt.options`. This argument is used to set `std` in `col_w_smd`.
`s.d.denom` | `character`; how the denominator for standardized mean differences should be calculated, if requested. See `col_w_smd` for allowable options. If not specified, `bal.tab()` will figure out which one is best based on the `par` component of the `sbwcau` object: if "att", "treated"; if "atc", "control"; otherwise "pooled". Abbreviations allowed.
`thresholds` | a named vector of balance thresholds, where the name corresponds to the statistic (i.e., in `stats`) that the threshold applies to. For example, to request thresholds on mean differences and variance ratios, one can set `thresholds = c(m = .05, v = 2)`. Requesting a threshold automatically requests the display of that statistic. See Details.
`weights` | a named list containing additional weights on which to assess balance. Each entry can be a vector of weights, the name of a variable in `data` that contains weights, or an object with a `get.w` method.
`cluster` | either a vector containing cluster membership for each unit or a string containing the name of the cluster membership variable in `data` or the `sbwcau` object. See `bal.tab.cluster` for details.
`imp` | either a vector containing imputation indices for each unit or a string containing the name of the imputation index variable in `data` or the original data set used in the call to `sbw()`. See `bal.tab.imp` for details. Not necessary if `data` is a `mids` object.
`abs` | `logical`; whether displayed balance statistics should be in absolute value or not.
`subset` | a `logical` or `numeric` vector denoting whether each observation should be included or which observations should be included. If `logical`, it should be the same length as the variables in the original call to `sbw()`. `NA`s will be treated as `FALSE`. This can be used as an alternative to `cluster` to examine balance on subsets of the data.
`quick` | `logical`; if `TRUE`, will not compute any values that will not be displayed. Set to `FALSE` if computed values not displayed will be used later.
`...` | further arguments to control display of output. See display options for details.

### Details

`bal.tab.sbwcau()` generates a list of balance summaries for the `sbwcau` object given, and functions similarly to `summarize()` in sbw.

The `thresholds` argument controls whether extra columns should be inserted into the Balance table describing whether the balance statistics in question exceeded or were within the threshold. Including these thresholds also creates summary tables tallying the number of variables that exceeded and were within the threshold and displaying the variables with the greatest imbalance on that balance measure.

### Value

If clusters are not specified, an object of class `"bal.tab"` containing balance summaries for the `sbwcau` object. See `bal.tab` for details.

If clusters are specified, an object of class `"bal.tab.cluster"` containing balance summaries within each cluster and a summary of balance across clusters. See `bal.tab.cluster` for details.

### Author(s)

Noah Greifer

### See Also

`bal.tab` for details of calculations.

### Examples

    library(sbw); data("lalonde", package = "cobalt")

    ## Stable balancing weights for the ATT
    sbw.out <- sbw(splitfactor(lalonde, drop.first = "if2"),
                   ind = "treat",
                   bal = list(bal_cov = c("age", "educ", "race_black",
                                          "race_hispan", "race_white",
                                          "married", "nodegree",
                                          "re74", "re75"),
                              bal_alg = FALSE,
                              bal_tol = .001),
                   par = list(par_est = "att"))

    bal.tab(sbw.out, un = TRUE, poly = 2)

[Package cobalt version 4.2.4 Index]