ECV_SG: ECV_SG
In BifactorIndicesCalculator: Bifactor Indices Calculator

Description Usage Arguments Value References See Also Examples

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.

1	ECV_SG(Lambda)

Lambda

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

A vector of ECVs for all factors

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

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)