www.andrew.cmu.edu Open in urlscan Pro
128.2.42.53  Public Scan

Form analysis
1 forms found in the DOM

GET http://www.free-css.com/

<form id="form1" method="get" action="http://www.free-css.com/">
</form>

Text Content

 * Home
 * SAS download
 * SAS examples
 * SAS documentation
 * Contact




TRAJ


GROUP-BASED MODELING 


OF LONGITUDINAL DATA




homeSAS download SAS examples SAS documentation contact


Traj estimates a discrete mixture model for clustering of longitudinal data
series. Groups may represent distinct subpopulations or
alternatively, components of a discrete approximation for a potentially complex
data distribution.

 

Supported distributions are: censored (or regular) normal, zero inflated (or
regular) Poisson, Beta, and Bernoulli distributions (logistic model). The
censored normal model is useful for psychometric scale data with censoring at a
scale minimum and/or scale maximum, the zero inflated Poisson model for count
data with more zeros than would be expected under the Poisson assumption, the
Bernoulli model for 0/1 data, and the Beta model for continuous data bounded in
the [0,1] interval. The model is appropriate for data with average values
changing smoothly as a function of the dependent variable (time, age, ...). Some
sharp changes can be handled through the inclusion of time dependent covariates.


TO INSTALL THE STATA VERSION:



net from https://www.andrew.cmu.edu/user/bjones/traj



net install traj



help traj



Note: If you have a Mac with the M1 or M2 chip, perform the following Stata
commands after installation:



in the “Applications” folder, locate the Stata app



right-click on the Stata app and click “Get Info”



click “Open using Rosetta”





Note: If you receive the error:



PKIX path building failed:
sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid
certification path to requested target



set sslrelax on



net from https://www.andrew.cmu.edu/user/bjones/traj



net install traj



set sslrelax off



REFERENCES:



A SAS procedure based on mixture models for estimating developmental
trajectories.

Advances in group-based trajectory modeling and a SAS procedure for estimating
them.

A note on a Stata plugin for estimating group-based trajectory models.

Group-based multi-trajectory modeling.

Group-based Trajectory Modeling Extended to Account for Nonrandom Participant
Attrition.

A novel methodological framework for multimodality, trajectory model-based
prognostication.

Using the Beta distribution in group-based trajectory models

Group-Based Trajectory Modeling in Clinical Research



LICENSE:



traj is open source licensed under

the 3-Clause BSD License (Open Source Initiative).


 

Copyright 2023 Bobby L. Jones.