subscore.Wainer {subscore}

Estimating true subscores using Wainer's augmentation method

Description

This function estimates subscores using Wainer's augmentation method (Wainer et. al., 2001) <doi:10.4324/9781410604729>. The central idea of this procedure is that, the estimation of subscores will be improved by shrinking the individual observed subscores towards some aggregate values (i.e., group mean subscores). The extent of the shrinkage depends on the closeness of the subscale being estimated with other subscales as well as reliabilities of all the subscales. Wainer's augmentation is a multivariate version of Kelly's formula (Kelly, 1947) <https://www.hup.harvard.edu/catalog.php?isbn=9780674330009>. For details of Wainer's augmentation subscoring method, please refer to Wainer et al. (2001) <doi:10.4324/9781410604729>.

Usage

subscore.Wainer(test.data)

Arguments

test.data

A list that contains item responses of all subtests and the entire test, which can be obtained using function 'data.prep'.

Value

summary

It contains statistical summary of the augmented subscores (mean, sd, and reliability).

Augmented.subscores

It contains augmented subscores that are obtained using Wainer's method.

References

Wainer, H., Vevea, J., Camacho, F., Reeve, R., Rosa, K., Nelson, L., Swygert, K., & Thissen, D. (2001). "Augmented scores - "Borrowing strength" to compute scores based on small numbers of items" In Thissen, D. & Wainer, H. (Eds.), Test scoring (pp.343 - 387). Mahwah, NJ: Lawrence Erlbaum Associates, Inc. doi:10.4324/9781410604729.

Kelley, T. L. (1947). Fundamentals of statistics. Harvard University Press. https://www.hup.harvard.edu/catalog.php?isbn=9780674330009.

Examples

 
       test.data<-data.prep(scored.data,c(3,15,15,20),
                            c("Algebra","Geometry","Measurement", "Math"))
        
        subscore.Wainer(test.data)
        
        subscore.Wainer(test.data)$summary
        subscore.Wainer(test.data)$subscore.augmented