New SSC package: mlmoderator — tools for cross-level interaction diagnostics in multilevel models

[Subir Hait]

Dear Statalist members,

I am pleased to announce that the package mlmoderator is now available for Stata (version 14.1 and above). The package provides a unified set of tools for probing, diagnosing, and visualizing cross-level interaction effects in multilevel models estimated using Stata’s mixed command.

The package integrates several commonly needed post-estimation procedures into a single workflow:

• mlmcenter — grand-mean, group-mean, and within-between centering
• mlmprobe — simple slopes at selected moderator values
• mlmjn — Johnson–Neyman intervals (analytical solution)
• mlmplot — publication-ready interaction plots
• mlmsummary — consolidated moderation results
• mlmvdecomp — decomposition of slope variance (fixed vs. random components)
• mlmsens — robustness diagnostics including ICC-shift and leave-one-cluster-out analysis

The goal of the package is to streamline interpretation and robustness assessment of cross-level interactions, particularly in hierarchical and longitudinal data settings.

Installation (from GitHub):
net install mlmoderator, /// from("https://raw.githubusercontent.com/causalfragility-lab/mlmoderator-Stata/main/") /// replace
The package has been approved for SSC and will be available there shortly.

A demonstration .do file and help documentation are included in the repository:
https://github.com/causalfragility-l...oderator-Stata

I would greatly appreciate any feedback, suggestions, or bug reports from the community.

Best regards,
Subir Hait
Department of Counseling, Educational Psychology, and Special Education
Michigan State University
ORCID: https://orcid.org/0009-0004-9871-9677

[Erik Ruzek]

This is fantastic, Subir Hait! Am I the only one who has trouble getting to the help file? When I type,

help mlmoderator

Stata takes me to the search results for mlmoderator. I am not sure why that is happening.

[Subir Hait]

Dear all,

This has now been corrected on SSC. The package-level help file (mlmoderator.sthlp) has been added, and help mlmoderator now works as intended after reinstalling the package.

Users can update the package by typing:
ssc install mlmoderator, replace

Many thanks to Erik Ruzek for identifying the issue.

Best regards,
Subir Hait