getMIX_UNI.addpara: Get Additional Parameters Related to Interval-specific...

In nlpsem: Linear and Nonlinear Longitudinal Process in Structural Equation Modeling Framework

Get Additional Parameters Related to Interval-specific Slopes, Interval-specific Changes and Values of Change-from- baseline for a Mixture Model or Multiple Group Model with Latent Change Score Models for Longitudinal Outcome

Description

This function derives additional parameters for a mixture model with latent change score models as submodels. In particular, it specifies the means and variances of interval-specific slopes, interval-specific changes, and values of change-from-baseline.

Usage

getMIX_UNI.addpara(
  dat,
  nClass,
  curveFun,
  intrinsic,
  t_var,
  records,
  growth_TIC,
  decompose,
  starts
)

Arguments

dat	A wide-format data frame, with each row corresponding to a unique ID. It contains the observed variables with repeated measurements and occasions for each longitudinal process, and time-invariant covariates (TICs) if any. It takes the value passed from getMIX() or getMGroup().
nClass	An integer specifying the number of classes for the mixture model or multiple group model. It takes the value passed from getMIX() or getMGroup().
curveFun	A string specifying the functional form of the growth curve. Supported options for latent change score models include: "quadratic" (or "QUAD"), "negative exponential" (or "EXP"), "Jenss-Bayley" (or "JB"), and "nonparametric" (or "NonP"). It takes the value passed from getMIX() or getMGroup().
intrinsic	A logical flag indicating whether to build an intrinsically nonlinear longitudinal model. It takes the value passed from getMIX() or getMGroup().
t_var	A string specifying the prefix of the column names corresponding to the time variable at each study wave. It takes the value passed from getMIX() or getMGroup().
records	A numeric vector specifying indices of the study waves. It takes the value passed from getMIX() or getMGroup().
growth_TIC	A string or character vector specifying the column name(s) of time-invariant covariate(s) contributing to the variability of growth factors if any. It takes the value passed from getMIX() or getMGroup().
decompose	An integer specifying the decomposition option for temporal states. Supported values include 0 (no decomposition), 1 (decomposition with interval-specific slopes as temporal states), 2 (decomposition with interval-specific changes as temporal states), and 3 (decomposition with change-from-baseline as temporal states). It takes the value passed from getTVCmodel(). It takes the value passed from getMIX() or getMGroup(). The argument is set as NULL when the submodel is a latent change score model.
starts	A list of initial values for the parameters, either takes the value passed from getMIX() or getMGroup(), or derived by the helper function getMIX.initial() or getMGroup.initial().

Value

A list containing the specification of the means and variances of interval-specific slopes, interval- specific changes, and values of change-from-baseline for latent change score models.

nlpsem documentation built on Sept. 13, 2023, 1:06 a.m.