ECV_SG {BifactorIndicesCalculator} R Documentation

## ECV_SG

### Description

Computes an ECV index for all factors which can be interpreted as the proportion of common variance of all items which is due to the specific factor; `ECV_SG` should be read 'ECV of a specific factor with respect to the general factor.' Here, ECV is computed with respect to the items of the general factor using the specific factor loadings in the numerator; Stucky and Edelen (2015, p. 199) refer to this index simply as 'specific-dimension ECV.' Note that `ECV_SG` of the general factor is simply the ECV. In the Excel version of the Bifactor Indices Calculator (Dueber, 2017), this form of ECV is referred to as 'ECV (S&E).' `ECV_SG` is called by `bifactorIndices` and the various convenience functions for exploratory models and/or Mplus output, which are the only functions in this package intended for casual users.

### Usage

```ECV_SG(Lambda)
```

### Arguments

 `Lambda` is a matrix of factor loadings. Be sure that all factors have the same variance before calling this function.

### Value

A vector of ECVs for all factors

### References

Dueber, D. M. (2017). Bifactor Indices Calculator: A Microsoft Excel-based tool to calculate various indices relevant to bifactor CFA models. doi: 10.13023/edp.tool.01

Stucky, B. D., & Edelen, M. O. (2015). Using hierarchical IRT models to create unidimensional measures from multidimensional data. In S. P. Reise & D. A. Revicki (Eds.), Handbook of item response theory modeling: Applications to typical performance assessment (pp.183-206). New York: Routledge.

`ECV_SS`, `ECV_GS`, `bifactorIndices`

### Examples

```Lambda <- matrix(c(.82, .10,   0,   0,
.77, .35,   0,   0,
.79, .32,   0,   0,
.66, .39,   0,   0,
.51,   0, .71,   0,
.56,   0, .43,   0,
.68,   0, .13,   0,
.60,   0, .50,   0,
.83,   0,   0, .47,
.60,   0,   0, .27,
.78,   0,   0, .28,
.55,   0,   0, .75),
ncol = 4, byrow = TRUE)
colnames(Lambda) <- c("General", "SF1", "SF2", "SF3")
ECV_GS(Lambda)

```

[Package BifactorIndicesCalculator version 0.2.2 Index]