# stMCA: Performs a 'standardized' MCA In GDAtools: A Toolbox for the Analysis of Categorical Data in Social Sciences, and Especially Geometric Data Analysis

## Description

Performs a 'standardized' Multiple Correspondence Analysis, i.e it takes MCA results and forces all the dimensions to be orthogonal to a supplementary 'control' variable.

## Usage

 `1` ```stMCA(resmca, control) ```

## Arguments

 `resmca` an object of class `'MCA'`, `'speMCA'`, `'csMCA'` or `'multiMCA'` `control` a list of 'control' variables

## Details

Standardized MCA unfolds in several steps. First, for each dimension of an input MCA, individual coordinates are used as dependent variable in a linear regression model and the 'control' variable is included as covariate in the same model. The residuals from every models are retained and bound together. The resulting data frame is composed of continuous variables and its number of columns is equal to the number of dimensions in the input MCA. Lastly, this data frame is used as input in a Principal Component Analysis.

## Value

Returns an object of class "stMCA". This object will be similar to `resmca` argument, still it does not comprehend modified rates, categories contributions and variables contributions.

Nicolas Robette

## References

Robette, Bry and Roueff, 2014, "Un dialogue de sourds dans le theatre statistique? Analyse geometrique des donnees et effets de structure", [http://nicolas.robette.free.fr/publis.html], forthcoming.

`plot.stMCA`, `MCA`, `speMCA`, `csMCA`, `multiMCA`, `PCA`

## Examples

 ``` 1 2 3 4 5 6 7 8 9 10``` ```## Performs a specific MCA on 'Music' example data set ## ignoring every 'NA' (i.e. 'not available') categories, ## and then performs a 'standardized' MCA controlling for age. data(Music) mca <- speMCA(Music[,1:5],excl=c(3,6,9,12,15)) plot(mca) textvarsup(mca,Music\$Age,col='red') stmca <- stMCA(mca,control=list(Music\$Age)) plot(stmca) textvarsup(stmca,Music\$Age,col='red') ```

### Example output

```Loading required package: FactoMineR