Help Desk

How many clusters do I need to fit a multilevel model?

In this edition of CBA Office Hours, Dan discusses a question that frequently comes up in our multilevel modeling workshop, namely, "How many clusters do I need to be able to fit a multilevel model?"  Here, clusters refers to upper-level units, so in the case of individuals nested within groups, the groups, and in the case of repeated measures, the individuals studied...
Keep Reading

Syntax for Computing Random Effect Estimates in SPSS

Many programs can be used to fit multilevel models. For instance, in our multilevel modeling summer workshop, we demonstrate three programs: SAS, SPSS, and Stata. Unlike SAS, Stata, and many other programs, however, SPSS does not currently offer the option to output estimates of the random effects. Obtaining estimates of the random effects can be useful for a variety of...
Keep Reading

The Human Desire to Categorize

Whether colors in the rainbow, notes in a musical scale, types of coffee, or country versus pop singers, there is a natural human desire to categorize objects and experiences. A story that recently appeared in the New York Times by Tom Vanderbilt presents a wonderful exploration of how we all find comfort in defining, seeking out, and confirming categories in...
Keep Reading

Evaluating Interaction Effects

Often the most interesting research question is not whether a relationship between two variables exists but rather under what conditions the relationship holds. Put in statistical terms, we are often less interested in main effects than we are in interactions or moderation. An interaction implies that the magnitude of the relation between two variables differs as a function of some...
Keep Reading

Using Listservs to get Advice

Although a bit old school, listservs such as SEMNET (for latent variable models) and the Multilevel Discussion List remain useful resources when grappling with quantitative modeling issues. You can search the archives to see if your question has come up before or post a new question to obtain fresh feedback / opinions from list members. Quick tip: use the “receive...
Keep Reading

CenterStat's Help Desk is a blog in which Dan and Patrick respond to commonly asked questions about a variety of topics behavioral, educational, and health research including experimental design, measurement, data analysis, and interpretation of findings. The responses are intentionally brief and concise, and additional resources are provided such as recommended readings, provision of exemplar data and computer code, or links to other potential learning materials. Readers are welcome to submit their own questions for future Help Desk responses at [email protected].

Livestream Workshops

Free Introduction to Structural Equation Modeling

May 10-12, 2023
Livestream & Replay Access
Instructors: Dan Bauer & Patrick Curran

Mixture Modeling and Latent Class Analysis

May 15-19, 2023
Livestream & Replay Access
Instructor: Dan Bauer & Doug Steinley

Applied Measurement Modeling

May 16-19, 2023
Livestream & Replay Access
Instructors: Patrick Curran & Greg Hancock

Applied Qualitative Research

May 22-26, 2023
Livestream & Replay Access
Instructors: Greg Guest & Emily Namey

Causal Inference

May 22-26, 2023
Livestream & Replay Access
Instructor: Doug Steinley

Multilevel Modeling

May 22-26, 2023
Livestream & Replay Access
Instructors: Dan Bauer & Patrick Curran

Modern Missing Data Analysis

June 5-7, 2023
Livestream & Replay Access
Instructor: Craig Enders

Machine Learning: Theory and Applications

June 5-9, 2023
Livestream & Replay Access
Instructor: Doug Steinley

Sample Size Planning for Power and Accuracy

June 6-8, 2023
Livestream & Replay Access
Instructor: Samantha Anderson

Analyzing Intensive Longitudinal Data

June 12-16, 2023
Livestream & Replay Access
Instructors: JP Laurenceau & Niall Bolger

Longitudinal Structural Equation Modeling

June 12-16, 2023
Livestream & Replay Access
Instructors: Dan Bauer & Patrick Curran