*! version 1.0 07Apr2015

help relicoef

Title

relicoef - Raykov's factor reliability coefficient

Description

relicoef computes Raykov's reliability coefficient (RRC) for factors from
confirmatory factor analyses, a measure which is commonly seen as a more
accurate one than that of Cronbach's alpha which is computed based on the
assumption of tau-equivalent measures.

Raykov (1997) proposes two different formulas for estimating reliability
coefficients which relicoef employs for the computation:

For factors without correlated errors (no error covariance)
RRC = (Sum of unstandardised loadings squared)*(factor variance)/
(Sum of unstandardised loadings squared)*(factor variance) +
(Sum of unstandardised error variances)

For factors with correlated errors (at least one error covariance)
RRC = (Sum of unstandardised loadings squared)*(factor variance)/
(Sum of unstandardised loadings squared)*(factor variance) +
(Sum of unstandardised error variances) +
(2*Sum of unstandardised error covariances)

KW: factor
KW: reliability
KW: coefficient
KW: scale

Examples

. use http://www.ats.ucla.edu/stat/stata/output/m255, clear

. keep item13 item14 item15 item25 item32

. qui sem (Factor1 -> item13 item14 item15) (Factor2 -> item25 item32)

. relicoef

. qui sem (Factor1 -> item13 item14 item15) (Factor2 -> item25 item32), cov(e.item13*e.item15)

. relicoef

Author

Mehmet Mehmetoglu
Department of Psychology
Norwegian University of Science and Technology
mehmetm@svt.ntnu.no

References

Raykov, T. (1997). Estimation of composite reliability for congeneric measures.
Applied Psychological Measurement, 21, 173-184.