Testing for Mediation and Moderation

Grayson N. Holmbeck provides tips for using multiple regression and SEM when testing for mediators and moderators.

Q&A

Making Sense of Mediators and Moderators

Helena Kraemer clarifies the roles of mediators, moderators, and interactions in RCTs.

Q&A

Defining a Pilot Study

Helena Kraemer shares her thoughts on what should and should not be called a pilot study.

Quick Tip - 1 minute 54 seconds

Post-Hoc Probing of Mediator and Moderator Effects

Grayson N. Holmbeck explains why post-hoc tests are important, and provides examples.

Q&A

Questions About Comorbidity

Husseini Manji advises investigators to address specific issues regarding comorbidity before beginning a study.

Quick Tip - 1 minute 22 seconds

Handling Missing Data

Roderick Rose suggests multiple imputation as a way of dealing with some types of missing data.

Q&A

Common Errors

Ignoring interactions and not centering are two common mistakes in data analysis, states Helena Kraemer.

Quick Tip - 1 minute 27 seconds

Statistical Training for MDs and PhDs

Both MDs and PhDs need to stay up-to-date with statistical methods, states Ruth M. O'Hara.

Quick Tip - 2 minutes 6 seconds

Consulting with a Statistician

Sue M. Marcus talks about how a statistician can help with your research design.

Q&A

Blocking and Matching

Helena Kraemer discusses reasons for taking a non-random sample.

Quick Tip - 1 minute 58 seconds