Four New Pages on R Statistics Help! Partial Correlation and Regressions

Need help with performing statistics in R?  Four new pages have been added to on the topic.  If you have a particular analysis that you need help with, feel free to email with questions or comments!

Dummy-Coded Regression in R

Partial Correlations in R

Quadratic Regression in R

Regression in R

Variable-Centered, Person-Centered, and Person-Specific ApproachesOrganizational Research Methods – Matt C. Howard, Michael E. Hoffman, 2017

Great news!  My recent article accepted by Organizational Research Methods is now online!  The article discusses the theoretical rationale behind three families of statistics: variable-centered, person-centered, and person-specific analyses.  If you have any questions about the article, or would like to figure out how to gain access to it, feel free to contact me at


Source: Variable-Centered, Person-Centered, and Person-Specific Approaches – Organizational Research Methods – Matt C. Howard, Michael E. Hoffman, 2017

New Calculator for Serial Mediation / Sequential Mediation

SerialMediationAfter my last Stats Help page on the “Sobel Test Formula for Serial Mediation / Sequential Mediation,” hereby called serial mediation, I realized that an adequate calculator for serial mediation sobel tests did not exist.  Of course, Hayes’s PROCESS macro in SPSS will calculate sobel tests for serial mediation, but it does so in a simple regression framework.  So, I created a calculator in excel which can be used in other frameworks, and it is now included at this link.  Also, the link provides all required information to use the calculator.

As always, email me at if you have any questions!