method note
Mediation analysis: from Baron–Kenny to bootstrapping
How is a mediation analysis run and reported?
Mediation is tested through the confidence interval of the indirect effect (a×b); Baron and Kenny's four steps and the Sobel test are no longer the standard. If a bias-corrected bootstrap confidence interval excludes zero, the indirect effect is significant. The 'full versus partial mediation' distinction is no longer recommended: a non-significant direct effect does not establish full mediation.
Why bootstrap
The indirect effect is a product of two coefficients, and the sampling distribution of that product is not normal. The Sobel test assumes normality and is therefore underpowered. Bootstrapping builds the distribution by resampling from the data; 5,000 resamples is a common choice.
Mediation in cross-sectional data
Mediation is a claim about process: X affects M, then M affects Y. Cross-sectional data collected at a single moment cannot show that ordering. A statistically significant indirect effect is not evidence of a causal process, and the limitation belongs in the write-up.
The work behind this note
- Mediating Role of Leader Member Exchange on the Relationship Between Emotional Intelligence and Conflict Management Strategies2013 · 70 citations
- Mediating Effects of Job Demands on the Relationship Between Type A Personality and Workaholism: A Study on Turkish Workers2013 · 21 citations
- The Mediating Role of the Motivation Potential Score in the Relationship between Goal Attainment Perception and Team Performance among Syrian Employees in İstanbul2025 · Article
- Effects of Trust on Job Satisfaction and Mediatory Role of New Identification between Trust and Job Satisfaction in Mergers2016 · 16 citations
Other method notes
- Exploratory or confirmatory? Which factor analysis, and whenShould I use exploratory or confirmatory factor analysis?
- Which fit index to report, and whenWhich fit indices should I report in structural equation modelling?
- Validity and reliability: what to report, and howHow are validity and reliability reported, and how do they differ?
Written for researchers and graduate students. Conventions described here are conventions, not rules — check them against your own design before you report.