ICPSR Summer Workshop on Categaorical Data Analysis
June 1519, 2015 at the Center for Research on Families at the University of MassachusettsAmherst
To enroll, contact the ICPSR Summer Program
FAQs ·
What to wear ·
Syllabus ·
Getting started with Stata ·
Lab files ·
Lecture files · Math Review ·Books
The workshop deals with the most important regression models for binary, ordinal, nominal and count outcomes. While advances in software make it simple to estimate these models, the effective interpretation of these nonlinear models is a vexingly difficult art that requires time, practice, and a firm grounding in the goals of your analysis and the characteristics of your model. The workshop begins by discussing the general objectives for interpreting results from any regression model and considers why these objectives are more difficult in nonlinear models. Concepts of estimation, testing, and identification are introduced in a quick review of the linear regression model. These ideas are used to develop the binary logit and probit models. Advanced methods of interpretation are introduced using Stata's margins command, with detailed examples on how to compute and interpreting average marginal effects, the distribution of effects, and related methods. Concepts from the binary model are used to develop the multinomial logit model for nominal outcomes, followed by the development of several models for ordinal outcomes. Finally, models for count data, including Poisson regression, negative binomial regression, and zero modified models are presented. While familiarity with Stata is recommended, the labs provide step by step instructions for those new to Stata.
Here are some highlights of the class.
 This year's workshop introduces a major update of Long and Freese's SPost comamnds. The new commands which are based on Stata's margins command allow methods of interpretation that heretofor were impractical.
 Mastering the powerful margins command using new SPost commands to control margins. Simple commands to compute average marginal effects, predictions using local means, and more.
 Automating your work to make complex analyses routine.
 Using graphical methods for exploring models.
 Finding out why "ordinal" models aren't always ordinal and why ordinal outcomes might not be ordinal.
While the labs use Stata and the lectures illustrate concepts with analyses from Stata, the class does not assume you have used Stata. The labs provide step by step instructions to help you learn Stata quickly. More experience Stata users can jump into more advanced exercises.
FAQs
 Can I bring my own data? Yes and I am pleased to meet with
you individually to discuss your research. It is important that the data has been "cleaned" since you won't have time to do that during the workshop. Ideally, the data should be converted to Stata format. Software is available at the workshop to
convert data from one format to another, but to be safe try to do this
before arriving. In Stata, type "help import" to learn about the data formats Stata can use.
 Do I have to use Stata?
If you don't want to try to use Stata at all, you probably won't want to take this course. If you have never used Stata but are willing to give it a try, you will have no
trouble doing the exercises. In lab you will be given handouts that walk you
through each step and the TA and I will be there to help. Will you be able
to apply what is done using other software? Yes, but but it is likely to
require a great deal more work. Why? Jeremy Freese and I have written the SPost commands that make complex computations
simple. I
am glad to talk with people about how you might approach these
computations in other software.
 Do I need to know everything on
the math review? It helps, but the most important thing is to be
sure you are comfortable with the log transformation and the exponential. If
you are confused by these, be sure to ask when you get here.
 What should I bring (to wear)? Bring a sweater or
light jacket for class! While the food is GREAT at UMAmherst, the room sometimes gets cold.
 Should I bring a laptop? In recent years, most people bring their own laptops for and we can install Stata on your computer with a temporary license for use during the workshop.
 And, what
else should I bring? I recommend a USB storage device to save your work.
 Will I have fun? I
certainly will, and I think you will too. ICPSR workshops are a
great way to learn new methods.
 Do I need to buy the books? You will be given extensive handouts with lecture notes.
While at ICPSR this might be all you need. The "with Stata"
book has less technical detail than the Sage book, but has a lot of
information of using Stata.
J. Scott Long, 1997, Regression Models for Categorical and Limited Dependent Variables. Advanced Quantitative Techniques in the Social Sciences, Volume 7. Sage Publications.. This books has a more technical discussion of topics in the class.
J. Scott Long and Jeremy Freese, 2014, Regression Models for Categorical Dependent Variables Using Stata, 3rd Edition. Stata Press: College Stata, TX.
Long, J.S. 2008, The Workflow of Data Analysis Using Stata. Stata Press: College Station, TX. If you plan to do a lot of data analysis, this book will save you a lot of time and make your work replicable.
Datasets and sample do files
To be added.
