Statistical Analysis With Latent Variables 
 
User’s Guide 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Linda K. Muthén 
Bengt O. Muthén 
 
 
 
 
 
 
 
Following is the correct citation for this document: 
 
Muthén, L.K. and Muthén, B.O. (1998-2010).  Mplus User’s Guide.  Sixth Edition. 
Los Angeles, CA: Muthén & Muthén 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Copyright © 1998-2010 Muthén & Muthén 
Program Copyright © 1998-2010 Muthén & Muthén 
Version 6 
April 2010 
 
 
The development of this software has been funded in whole or in part with Federal funds 
from the National Institute on Alcohol Abuse and Alcoholism, National Institutes of 
Health, under Contract No. N44AA52008 and Contract No. N44AA92009.    
 
 
Muthén & Muthén 
3463 Stoner Avenue 
Los Angeles, CA  90066 
Tel: (310) 391-9971 
Fax: (310) 391-8971 
Web: www.StatModel.com 
Support@StatModel.com 
TABLE OF CONTENTS 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Chapter 1:  Introduction 
 
Chapter 2:  Getting started with Mplus 
 
Chapter 3:  Regression and path analysis 
 
Chapter 4:  Exploratory factor analysis 
 
Chapter 5:  Confirmatory factor analysis and structural equation modeling  
 
Chapter 6:  Growth modeling and survival analysis   
 
Chapter 7:  Mixture modeling with cross-sectional data 
 
Chapter 8:  Mixture modeling with longitudinal data  
 
Chapter 9:  Multilevel modeling with complex survey data   
 
Chapter 10: Multilevel mixture modeling 
 
Chapter 11: Missing data modeling and Bayesian analysis 
 
Chapter 12: Monte Carlo simulation studies   
 
Chapter 13: Special features   
 
Chapter 14: Special modeling issues   
 
Chapter 15: TITLE, DATA, VARIABLE, and DEFINE commands  
 
Chapter 16: ANALYSIS command 
 
Chapter 17: MODEL command 
 
Chapter 18: OUTPUT, SAVEDATA, and PLOT commands 
 
Chapter 19: MONTECARLO command 
 
Chapter 20: A summary of the Mplus language 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
    1 
  13 
  19 
  41 
  51 
  97 
141 
197 
233 
289 
337 
357       
391 
407 
449 
519 
567 
633 
689 
711 
 
 
PREFACE 
 
We started to develop Mplus fifteen years ago with the goal of providing researchers with 
powerful new statistical modeling techniques.  We saw a wide gap between new 
statistical methods presented in the statistical literature and the statistical methods used 
by researchers in substantively-oriented papers.  Our goal was to help bridge this gap 
with easy-to-use but powerful software.  Version 1 of Mplus was released in November 
1998; Version 2 was released in February 2001; Version 3 was released in March 2004; 
Version 4 was released in February 2006; and Version 5 was released in November 2007.  
We are now proud to present the new and unique features of Version 6.  With Version 6, 
we have gone a considerable way toward accomplishing our goal, and we plan to 
continue to pursue it in the future. 
 
The new features that have been added between Version 5 and Version 6 would never 
have been accomplished without two very important team members, Tihomir 
Asparouhov and Thuy Nguyen.  It may be hard to believe that the Mplus team has only 
two programmers, but these two programmers are extraordinary.  Tihomir has developed 
and programmed sophisticated statistical algorithms to make the new modeling possible.  
Without his ingenuity, they would not exist.  His deep insights into complex modeling 
issues and statistical theory are invaluable.  Thuy has developed the post-processing 
graphics module and the Mplus editor and language generator.  In addition, Thuy has 
programmed the Mplus language and is responsible for keeping control of the entire code 
which has grown enormously.  Her unwavering consistency, logic, and steady and calm 
approach to problems keep everyone on target.  We feel fortunate to work with such a 
talented team.  Not only are they extremely bright, but they are also hard-working, loyal, 
and always striving for excellence.  Mplus Version 6 would not have been possible 
without them.   
 
Another important team member is Michelle Conn.  Michelle was with us at the 
beginning when she was instrumental in setting up the Mplus office and has been 
managing the office for the past six years.  In addition, Michelle is responsible for 
creating the pictures of the models in the example chapters of the Mplus User’s Guide.  
She has patiently and quickly changed them time and time again as we have repeatedly 
changed our minds.  She is also responsible for keeping the website updated and 
interacting with customers.  Her calm under pressure is much appreciated.  Jean 
Maninger joined the Mplus team after Version 4 was released.  Jean works with Michelle 
and has proved to be a valuable team member. 
We would also like to thank all of the people who have contributed to the development of 
Mplus in past years.  These include Stephen Du Toit, Shyan Lam, Damir Spisic, Kerby 
Shedden, and John Molitor. 
 
Part of the work has been supported by SBIR contracts from NIAAA that we 
acknowledge gratefully. We thank Bridget Grant for her encouragement in this work. 
 
Linda K. Muthén 
Bengt O. Muthén 
Los Angeles, California 
April 2010 
 
 
Introduction 
CHAPTER 1 
INTRODUCTION 
 
 
Mplus is a statistical modeling program that provides researchers with a 
flexible  tool  to  analyze  their  data.    Mplus  offers  researchers  a  wide 
choice  of  models,  estimators,  and  algorithms  in  a  program  that  has  an 
easy-to-use interface and graphical displays of data and analysis results.  
Mplus allows the analysis of both cross-sectional and longitudinal data, 
single-level  and  multilevel  data,  data 
that  come  from  different 
populations with either observed or unobserved heterogeneity, and data 
that  contain  missing  values.    Analyses  can  be  carried  out  for  observed 
variables  that  are  continuous,  censored,  binary,  ordered  categorical 
(ordinal),  unordered  categorical  (nominal),  counts,  or  combinations  of 
these  variable  types.    In  addition,  Mplus  has  extensive  capabilities  for 
Monte  Carlo  simulation  studies,  where  data  can  be  generated  and 
analyzed according to any of the models included in the program. 
 
The Mplus modeling framework draws on the unifying theme of latent 
variables.  The generality of the Mplus modeling framework comes from 
the  unique  use  of  both  continuous  and  categorical  latent  variables.  
Continuous latent variables are used to represent factors corresponding 
to  unobserved  constructs,  random  effects  corresponding  to  individual 
differences in development, random effects corresponding to variation in 
coefficients across groups in hierarchical data, frailties corresponding to 
unobserved  heterogeneity  in  survival  time,  liabilities  corresponding  to 
genetic  susceptibility  to  disease,  and  latent  response  variable  values 
corresponding to missing data.  Categorical latent variables are used to 
represent  latent  classes  corresponding  to  homogeneous  groups  of 
individuals, 
types  of 
development 
components 
corresponding  to  finite  mixtures  of  unobserved  populations,  and  latent 
response variable categories corresponding to missing data.   
 
trajectory  classes  corresponding 
in  unobserved  populations,  mixture 
latent 
to 
THE Mplus MODELING FRAMEWORK 
 
The  purpose  of  modeling  data  is  to  describe  the  structure  of  data  in  a 
simple  way  so  that  it  is  understandable  and  interpretable.    Essentially, 
the  modeling  of  data  amounts  to  specifying  a  set  of  relationships 
 
                                                                                                                 1
between  variables.    The  figure  below  shows  the  types  of  relationships 
that  can  be  modeled  in  Mplus.    The  rectangles  represent  observed 
variables.  Observed variables can be outcome variables or background 
variables.    Background  variables  are  referred  to  as  x;  continuous  and 
censored  outcome  variables  are  referred  to  as  y;  and  binary,  ordered 
categorical  (ordinal),  unordered  categorical  (nominal),  and  count 
outcome  variables  are  referred  to  as  u.    The  circles  represent  latent 
variables.  Both continuous and categorical latent variables are allowed.  
Continuous  latent  variables  are  referred  to  as  f.    Categorical  latent 
variables are referred to as c.   
 
The  arrows  in  the  figure  represent  regression  relationships  between 
variables.  Regressions relationships that are allowed but not specifically 
shown  in  the  figure  include  regressions  among  observed  outcome 
variables,  among  continuous  latent  variables,  and  among  categorical 
latent  variables.    For  continuous  outcome  variables,  linear  regression 
models  are  used.    For  censored  outcome  variables,  censored  (tobit) 
regression  models  are  used,  with  or  without  inflation  at  the  censoring 
point.    For  binary  and  ordered  categorical  outcomes,  probit  or  logistic 
regressions  models  are  used.    For  unordered  categorical  outcomes, 
multinomial  logistic  regression  models  are  used.    For  count  outcomes, 
Poisson  and  negative  binomial  regression  models  are  used,  with  or 
without inflation at the zero point.    
CHAPTER 1 
2