Causal Mediation Analysis in Single Case Experimental Designs: Introduction to the Special Issue

Area of Science:

• Health Research Methodology
• Psychometrics
• Behavioral Science

Background:

• Causal mediation analysis traditionally focused on between-subjects designs.
• Single Case Experimental Designs (SCEDs) are vital in applied health research for evaluating treatment effects.
• Limited methods existed for mediation analysis within SCEDs.

Purpose of the Study:

• To present novel methods for causal mediation analysis specifically tailored for SCEDs.
• To enable the evaluation of causal indirect effects in individual participants.
• To advance the application of mediation analysis in health research using SCEDs.

Main Methods:

• The special issue features articles detailing advanced quantitative techniques for mediator testing in SCEDs.
• Approaches are proposed to relax restrictive statistical assumptions for real-world data.
• Illustrations of mediation analysis are provided using both real and simulated SCED data.

Main Results:

• This collection offers researchers robust methods to analyze mediation within SCEDs.
• The presented techniques allow for a more nuanced understanding of treatment effects at the individual level.
• The findings support the extension of mediation analysis beyond traditional group designs.

Conclusions:

• The development of causal mediation analysis for SCEDs is crucial for personalized diagnosis, treatment, and prevention strategies.
• These methods enhance the interpretability and utility of SCEDs in health research.
• This work bridges a gap in methodology, facilitating deeper insights into treatment mechanisms.