Multilevel Data Analysis - Don Hedeker

PDF Files, Datasets, Examples, and Programs


Multilevel Data

Reading material: Hedeker, D., Gibbons, R.D., & Flay, B.R. (1994). Random-effects regression models for clustered data with an example from smoking prevention research. Journal of Consulting and Clinical Psychology, 62, 757-765. (pdf file)

Slides: Multilevel Analysis: An Applied Introduction (pdf file)

Example using SAS PROC MIXED:
TVSFPMIX.SAS - SAS code for analysis of TVSFP dataset using a few different MIXED models. Also includes individual-level and aggregate-level analyses.
TVSFP2B.DAT - ASCII data file for example above.

Example using SPSS MIXED:
TVSFPC.SPS - SPSS code for analysis of TVSFP dataset using a few different MIXED models.
TVSFPC.SAV – SPSS .SAV file for the example above.


Longitudinal Continuous Data

Reading material: Hedeker, D. (2004). An introduction to growth modeling.  In D. Kaplan (Ed.), Quantitative Methodology for the Social Sciences. Thousand Oaks CA: Sage Publications. (pdf file)

Slides: Introduction to Mixed Models for Longitudinal Data for Longitudinal Continuous Data (pdf file)

Examples using SAS PROC MIXED:
1. Analysis of Riesby dataset.  This example has a few different PROC MIXED specifications, and includes a grouping variable and curvilinear effect of time. (SAS code and output)

2. This handout shows how empirical Bayes estimates can be output to a dataset in order to calculate estimated individual scores at all timepoints. (SAS code and output)

3.  This handout has the analysis considering the time-varying drug plasma levels, separating the within-subjects from the between-subjects effects for these time-varying covariates. (SAS code and output)

Datasets:

Riesby dataset – for examples 1 and 2, the variable order and names are indicated in the above syntax files.

Riesby dataset with time-varying covariates – for example 3, the variable order and names are indicated in the above syntax.

 

Examples using SPSS MIXED:
1. Analysis of Riesby dataset.  This example has a few different MIXED specifications, and includes a grouping variable and curvilinear effect of time.  It also shows how to get plots of the empirical Bayes estimates. (SPSS code)

2.  This handout has the analysis considering the time-varying drug plasma levels, separating the within-subjects from the between-subjects effects for these time-varying covariates. (SPSS code)

Datasets:

Riesby dataset  – a SPSS .SAV file - for example 1.

Riesby dataset with time-varying covariates – a SPSS .SAV file - for example 2.


Missing Values in Longitudinal Data

Reading material: Hedeker, D., & Gibbons, R.D. (1997).  Application of random-effects pattern-mixture models for missing data in longitudinal studies.  Psychological Methods, 2, 64-78. (pdf file)

Slides: Mixed Pattern-Mixture and Selection Models for Missing Data (pdf file)

Examples using SAS PROC MIXED:
schizpm.sas - SAS code for pattern-mixture model analysis of NIMH Schizophrenia dataset.

schizsel.sas - SAS code for shared parameter (selection) model analysis of NIMH Schizophrenia dataset.

SCHIZREP.DAT - ASCII datafile for examples above.

Example using SPSS MIXED:
schizpm.sps - SPSS code for pattern-mixture model analysis of NIMH Schizophrenia dataset.

SCHIZREP.SAVSPSS  .SAV file for example above.


Longitudinal Dichotomous Data

 

Reading material: Hedeker, D. (2005).  Generalized linear mixed models.  In B. Everitt & D. Howell (Eds.),  Encyclopedia of Statistics in Behavioral Science. Wiley, New York.  (pdf file) 

Slides: Mixed Models for Longitudinal Dichotomous Data (pdf file)

Examples using SAS:
Analysis of the NIMH Schizophrenia dataset.  This handout provides SAS (PROC LOGISTIC, GLIMMIX, NLMIXED) code for running ordinary logistic regression and mixed-effects logistic regression.  (SAS code)

Dataset: SCHIZ dataset - the variable order and names are indicated in the example above.

PROC IML code to obtain marginalized probability estimates from the random intercept model estimates (SAS code)

PROC IML code to obtain marginalized probability estimates from the random trend model estimates   (SAS code)

GEE analysis of the NIMH Schizophrenia dataset using SAS PROC GENMOD (SAS code)


Longitudinal Ordinal and Nominal Data

 

Reading material: Hedeker, D. (2008).  Multilevel models for ordinal and nominal variables.  In J. de Leeuw & E. Meijer (Eds.), Handbook of Multilevel Analysis.  Springer, New York.  (pdf file) 

Slides: Mixed Models for Longitudinal Ordinal and Nominal Data (pdf file)

Examples using SAS:
schzonl.sas - SAS code for mixed-effects proportional odds regression analysis of NIMH Schizophrenia data.  schizx1.dat - ASCII datafile.

schzofit.sas - SAS IML code to obtain marginal probability estimates based on mixed-effects proportional odds regression analysis of NIMH Schizophrenia data.

sandonl.sas - SAS code for mixed-effects proportional odds and non-proportional odds analyses of San Diego homelessness data. sdhouse.dat - ASCII datafile.

sandofit.sas - SAS IML code to obtain marginal probability estimates based on mixed-effects proportional odds and non-proportional odds regression analysis of San Diego homelessness data.

sandnnl.sas - SAS code for mixed-effects nomial regression analyses of San Diego homelessness data.

sandnfit.sas - SAS IML code to obtain marginal probability estimates based on mixed-effects inomial regression analysis of San Diego homelessness data.


Sample Size Estimation for Longitudinal Studies

Reading material: Hedeker, D., Gibbons, R.D., & Waternaux, C. (1999).  Sample size estimation for longitudinal designs with attrition: comparing time-related contrasts between two groups.  Journal of Educational and Behavioral Statistics, 24:70-93. (pdf file)

Slides: (pdf file)

RMASS2.EXE contains:
- executable program for sample size determination based on this paper.
RMASS2.PDF contains:
- PDF version of program guide


More information and materials:

Don's short course on Longitudinal Data Analysis

Don's 15-week course on Longitudinal Data Analysis

The MIX website

Any questions or comments to Don: hedeker@uic.edu