stratrs {BART} | R Documentation |

## Perform stratified random sampling to balance outcomes

### Description

This function is used to perform stratified random sampling to balance outcomes among the shards.

### Usage

```
stratrs(y, C=5, P=0)
```

### Arguments

`y` |
The binary/categorical/continuous outcome. |

`C` |
The number of shards to break the data set into. |

`P` |
For continuous data, we break the range into P segments via the quantiles. Specifying, P=20 seems to work reasonably well. |

### Details

To perform BART with large data sets, random sampling is employed
to break the data into `C`

shards. Each shard should be
balanced with respect to the outcome. For binary/categorical
outcomes, stratified random sampling is employed with this function.

### Value

A vector is returned with each element assigned to a shard.

### See Also

### Examples

```
set.seed(12)
x <- rbinom(25000, 1, 0.1)
a <- stratrs(x)
table(a, x)
z <- pmin(rpois(25000, 0.8), 5)
b <- stratrs(z)
table(b, z)
```

[Package

*BART*version 2.9.7 Index]