Calculates Cronbach's alpha, a measure of statistical reliability. Cronbach's alpha is a simple measure
of "consistency" of a data set, where a high value implies higher reliability/consistency. The
selection of indicators via `get_data()`

allows to calculate the measure on any group of
indicators or aggregates.

## Arguments

- coin
A coin or a data frame containing only numerical columns of data.

- dset
The name of the data set to apply the function to, which should be accessible in

`.$Data`

.- iCodes
Indicator codes to retrieve. If

`NULL`

(default), returns all iCodes found in the selected data set. See`get_data()`

.- Level
The level in the hierarchy to extract data from. See

`get_data()`

.- ...
Further arguments passed to

`get_data()`

, other than those explicitly specified here.- use
Argument to pass to stats::cor to calculate the covariance matrix. Default

`"pairwise.complete.obs"`

.

## Details

This function simply returns Cronbach's alpha. If you want a lot more details on reliability, the 'psych' package has a much more detailed analysis.

This function replaces the now-defunct `getCronbach()`

from COINr < v1.0.

## Examples

```
# build example coin
coin <- build_example_coin(up_to = "new_coin", quietly = TRUE)
# Cronbach's alpha for the "P2P" group
get_cronbach(coin, dset = "Raw", iCodes = "P2P", Level = 1)
#> [1] 0.05126659
```