alpha_curve: Cronbach-Mesbah Curve

In SICSresearch/LatentREGpp: Item Response Theory Implemented in R and Cpp

Description

Assess the unidimensionality of a set of items from alpha coefficient.

Usage

alpha_curve(data)

Arguments

data	a Dataframe that holds the test response data

Details

Constructs the curve by iteration:
1. Compute alpha using all items.
2. Remove one item from the scale. The removed item is the one which leaves the scale with its maximum alpha value. If we remove a bad item, the alpha coefficient will increase. Whereas if we remove a good item, the alpha must decrease.
3. Repeat until only two items remain.
This function was extracted from CMC_1.0 package.

Value

The number of items used to calculate the coefficient.

The maximum value of the alpha coefficient calculated at each step.

The item removed at each step.

Tue Cronbach-Mesbah curve plot.

References

Cameletti, M. & Caviezel, V. (2010). Checking the unidimensionality in R using the Cronbach-Mesbah curve.

Mesbah, M. (2010). Statistical quality of life. In "Method and Applications of Statistics in the Life and Health Sciences", N. BalakrishnanEd., Wiley, pp. 839-864.

SICSresearch/LatentREGpp documentation built on May 9, 2019, 11:13 a.m.