reliability {cSEM}  R Documentation 
Reliability
Description
Compute several reliability estimates. See the Reliability section of the cSEM website for details.
Usage
calculateRhoC(
.object = NULL,
.model_implied = TRUE,
.only_common_factors = TRUE,
.weighted = FALSE
)
calculateRhoT(
.object = NULL,
.alpha = 0.05,
.closed_form_ci = FALSE,
.only_common_factors = TRUE,
.output_type = c("vector", "data.frame"),
.weighted = FALSE,
...
)
Arguments
.object 
An R object of class cSEMResults resulting from a call to 
.model_implied 
Logical. Should weights be scaled using the modelimplied
indicator correlation matrix? Defaults to 
.only_common_factors 
Logical. Should only concepts modeled as common
factors be included when calculating one of the following quality criteria:
AVE, the FornellLarcker criterion, HTMT, and all reliability estimates.
Defaults to 
.weighted 
Logical. Should estimation be based on a score that uses
the weights of the weight approach used to obtain 
.alpha 
An integer or a numeric vector of significance levels.
Defaults to 
.closed_form_ci 
Logical. Should a closedform confidence interval be computed?
Defaults to 
.output_type 
Character string. The type of output. One of "vector" or "data.frame". Defaults to "vector". 
... 
Ignored. 
Details
Since reliability is defined with respect to a classical true score measurement
model only concepts modeled as common factors are considered by default.
For concepts modeled as composites reliability may be estimated by setting
.only_common_factors = FALSE
, however, it is unclear how to
interpret reliability in this case.
Reliability is traditionally based on a test score (proxy) based on unit weights.
To compute congeneric and tauequivalent reliability based on a score that
uses the weights of the weight approach used to obtain .object
use .weighted = TRUE
instead.
For the tauequivalent reliability ("rho_T
" or "cronbachs_alpha
") a closedform
confidence interval may be computed (Trinchera et al. 2018) by setting
.closed_form_ci = TRUE
(default is FALSE
). If .alpha
is a vector
several CI's are returned.
Value
For calculateRhoC()
and calculateRhoT()
(if .output_type = "vector"
)
a named numeric vector containing the reliability estimates.
If .output_type = "data.frame"
calculateRhoT()
returns a data.frame
with as many rows as there are
constructs modeled as common factors in the model (unless
.only_common_factors = FALSE
in which case the number of rows equals the
total number of constructs in the model). The first column contains the name of the construct.
The second column the reliability estimate.
If .closed_form_ci = TRUE
the remaining columns contain lower and upper bounds
for the (1  .alpha
) confidence interval(s).
Functions

calculateRhoC()
: Calculate the congeneric reliability 
calculateRhoT()
: Calculate the tauequivalent reliability
References
Trinchera L, Marie N, Marcoulides GA (2018). “A Distribution Free Interval Estimate for Coefficient Alpha.” Structural Equation Modeling: A Multidisciplinary Journal, 25(6), 876–887. doi:10.1080/10705511.2018.1431544.