# calculateIndicatorCor

##### Internal: Calculate indicator correlation matrix

Calculate the indicator correlation matrix using conventional or robust methods.

- Keywords
- internal

##### Usage

```
calculateIndicatorCor(
.X_cleaned = NULL,
.approach_cor_robust = "none"
)
```

##### Arguments

- .X_cleaned
A data.frame of processed data (cleaned and ordered). Note:

`X_cleaned`

may not be scaled!- .approach_cor_robust
Character string. Approach used to obtain a robust indicator correlation matrix. One of: "

*none*" in which case the standard Bravais-Person correlation is used, "*spearman*" for the Spearman rank correlation, or "*mcd*" via`MASS::cov.rob()`

for a robust correlation matrix. Defaults to "*none*". Note that many postestimation procedures (such as`testOMF()`

or`fit()`

implicitly assume a continuous indicator correlation matrix (e.g. Bravais-Pearson correlation matrix). Only use if you know what you are doing.

##### Details

If `.approach_cor_robust = "none"`

(the default) the type of correlation computed
depends on the types of the columns of `.X_cleaned`

(i.e., the indicators)
involved in the computation.

`Numeric-numeric`

If both columns (indicators) involved are numeric, the Bravais-Pearson product-moment correlation is computed (via

`stats::cor()`

).`Numeric-factor`

If any of the columns is a factor variable, the polyserial correlation Drasgow1988cSEM is computed (via

`polycor::hetcor()`

).`Factor-factor`

If both columns are factor variables, the polychoric correlation Drasgow1988cSEM is computed (via

`polycor::hetcor()`

).

Note: logical input is treated as a 0-1 factor variable.

If `"mcd"`

(= minimum covariance determinant), the MCD estimator
Rousseeuw1999cSEM, a robust covariance estimator, is applied
(via `MASS::cov.rob()`

).

If `"spearman"`

, the Spearman rank correlation is used (via `stats::cor()`

).

##### Value

A list with elements:

`$S`

The (K x K) indicator correlation matrix

`$cor_type`

The type(s) of indicator correlation computed ( "Pearson", "Polyserial", "Polychoric")

`$thre_est`

Currently ignored (NULL)

##### References

*Documentation reproduced from package cSEM, version 0.1.0, License: GPL-3*