Estimate the parameters of model constructed using the slca
function.
Usage
estimate(x, ...)
# S3 method for class 'slca'
estimate(x, data,
method = c("em", "hybrid", "nlm"),
fix2zero = NULL,
control = slcaControl(), ...)
Arguments
- x
an
slca
object defining SLCM model to be estimated.- ...
additional arguments.
- data
a
data.frame
object containing observed categorical variables incorporated in the model.- method
estimation method for SLCM parameters. The default is
"em"
, which employs expecation-maximization (EM) algorithm for estimation; the alternative"nlm"
, utilizesnlm
function for Newton-Raphson algorithm. The"hybrid"
method begins with the EM algorithm and concludes with thenlm
function for refined estimation.- fix2zero
a
vector
of parameters to be restricted to zero. The details of restriction is given under 'Details'- control
a
list
of control for the estimation procedure. Used to modify default values in slcaControl.
Value
An object of class slca
and estimated
with an following elements:
- model
a
list
describing of the model.- method
the method used for estimation
- arg
the brief model description used during the estimation.
- mf
the data.frame used for estimation.
- par
the log of the estimated paramters.
- logit
the log-odds of the estimated parameters.
- score
the score function for the estimated parameters.
- posterior
the
list
of posterior probablities for each latent class variable.- convergence
a logical indicator of whether convergence was achieved.
- loglikelihood
the loglikelihood of the estimated model.
- control
the control values used during the estimation process.
This returned object can be further processed using the param functions to extract the estimated parameters or their respective standard errors. Additionally, the regress function enables logistic regression analysis using three-step approach to evaluate the effect of external variables on latent class variables.
Details
To constrain certain parameters to zero, use the fix2zero
argument. Each parameter is associated with a unique index. You can identify the index of a specific parameter by invoking the param function with the index = TRUE
argument. To apply these constraints, include the relevant parameter indices in the fix2zero
argument.