# auc: Compute the Area Under the pp_plot Curve Calculates the area... In DJAnderson07/esvis: Visualization and Estimation of Effect Sizes

## Description

Compute the Area Under the pp_plot Curve Calculates the area under the `pp` curve. The area under the curve is also a useful effect-size like statistic, representing the probability that a randomly selected individual from the `x` distribution will have a higher value than a randomly selected individual from the `y` distribution.

## Usage

 `1` ```auc(data, formula, ref_group = NULL, rename = TRUE) ```

## Arguments

 `data` The data frame used for estimation - ideally structured in a tidy format. `formula` A formula of the type `out ~ group` where `out` is the outcome variable and `group` is the grouping variable. Note this variable can include any arbitrary number of groups. Additional variables can be included with `+` to produce separate estimates by the secondary or tertiary variables of interest (e.g., ```out ~ group + characteristic1 + characteristic2```). `ref_group` Optional. A character vector or forumla listing the reference group levels for each variable on the right hand side of the formula, supplied in the same order as the formula. Note that if using the formula version, levels that are numbers, or include hyphens, spaces, etc., should be wrapped in back ticks (e.g., `ref_group = ~ Active + `Non-FRL``, or `ref_group = ~`8``). When in doubt, it is safest to use the back ticks, as they will not interfere with anything if they are not needed. See examples below for more details. `rename` Used primarily for internal purposes. Should the column names be renamed to reference the focal and reference groups? Defaults to `TRUE`.

## Value

By default the area under the curve for all possible pairings of the grouping factor are returned.

## Examples

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20``` ```# Calculate AUC for all pairwise comparisons auc(star, reading ~ condition) # Report only relative to regular-sized classrooms auc(star, reading ~ condition, ref_group = "reg") # Report by ELL and FRL groups for each season, compare to non-ELL students # who were not eligible for free or reduced price lunch in the fall (using # the formula interface for reference group referencing). auc(benchmarks, math ~ ell + frl + season, ref_group = ~`Non-ELL` + `Non-FRL` + Fall) # Same thing but with character vector supplied, rather than a formula auc(benchmarks, math ~ ell + frl + season, ref_group = c("Non-ELL", "Non-FRL", "Fall")) ```

DJAnderson07/esvis documentation built on June 14, 2018, 7:06 a.m.