SuperMix  |  Mixed-Up Suite  |  NPPL  |  LPL

DRUGStat is an easy to use system for determining which drugs are potentially harmful or protective relative to all other drugs in the specific class of drugs of interest.


MVPreg computes a general multivariate probit regression model for the analysis of multivariate binary data.


MIXZIP provides the maximum marginal likelihood estimates of mixed-effects Zero-Inflated Poisson (ZIP) regression models.

Authors list:
Kwan Hur, Robert D. Gibbons and Kush Kapur
Graphical user interface by Dave Patterson

The RMASS program computes sample size for three-level mixed-effects linear regression models for the analysis of clustered longitudinal data. Three-level designs are used in many areas, but in particular, multi-center randomized longitudinal clinical trials in medical or health-related research. In this case, level 1 represents measurement occasion, level 2 represents subject, and level 3 represents center.

The model allows for random-effects of the time trends at both the subject-level and the center-level. The sample size determinations in this program are based on the requirements for a test of treatment by time interaction(s) for designs based on either subject-level or cluster-level randomization.

The approach is general with respect to sampling proportions and number of groups, and it allows for differential attrition rates over time. The general methodology is discussed in Sample Size Determination for Hierarchical Longitudinal Designs with Differential Attrition Rates View PDF

Authors list:
Anindya Roy, Dulal K. Bhaumik, Subhash Aryal and Robert D. Gibbons
Web interface by Monica Jercan

The BIFACTOR program estimates the bifactor model for ordinal and dichotomous data.

Authors list:
Robert D. Gibbons and Donald Hedeker

SuperMix extends the functionality available in the Mixed-Up Suite by providing advanced data handling, the ability to reference columns by name, sophisticated import and export capability, visualization of data and results, increased analysis speed and additional statistical engine functions.

SuperMix has been developed by Scientific Software International under an SBIR Phase II contract N44MH32056. The application will fit models with continuous, count, ordinal, nominal, and survival outcome variables with nested data, allowing for up to three levels of nesting. For a more in-depth look at SuperMix and to download a free fully functional 15-day trial edition vist the SSI SuperMix homepage.

The Mixed-Up Suite

The Mixed-up Suite provides mixed-effects regression functionality not available anywhere else — at any price. MIXOR, MIXREG, MIXNO and MIXPREG are based on the collaborative effort of Drs. Donald Hedeker and Robert D. Gibbons of the University of Illinois at Chicago and University of Chicago, respectively. Discerning Systems Inc. produced the user interfaces around the computer programs written by Don Hedeker.

The work was supported by the National Institute of Mental Health and the MacArthur Foundation, and the programs are available free of charge for download from the MIXOR/MIXREG homepage located at the University of Illinois at Chicago.

Nonparametric Prediction Interval for Analysis of Microarray Data

The statistical methodology implemented in this applet is based on a nonparametric prediction interval described in Sequential Prediction Bounds for Identifying Differentially Expressed Genes in Replicated Microarray Experiments View PDF by Robert D. Gibbons, Dulal K. Bhaumik, David R. Cox, Dennis R. Grayson, John M. Davis, and Rajiv P. Sharma.

Lognormal Prediction Limit for the Arithmetic Mean of n future samples

This program computes the 95% lognormal prediction limit for a future mean of n samples based on a historical set of m samples.

  Last updated April 25, 2013. Copyright © 2003-2013 Center for Health Statistics. All Rights Reserved.

Center for Health Statistics Logo University of Chicago Home Center for Health Statistics Home