Compare methods

	Sibling Fixed-Effects Design	Chains-of-Risk Model
Field	Social Epidemiology	Social Epidemiology
Family	Regression model	Process / pipeline
Year of origin	2013	2003
Originator	Brian D'Onofrio, Benjamin Lahey, Eric Turkheimer & Paul Lichtenstein; Thomas Frisell et al.	Diana Kuh & Yoav Ben-Shlomo (life-course glossary and conceptual models)
Type	Within-family fixed-effects design for confounding control	Sequential-mediation model of linked life-course exposures
Seminal source	Frisell, T., Oberg, S., Kuja-Halkola, R., & Sjolander, A. (2012). Sibling Comparison Designs: Bias From Non-Shared Confounders and Measurement Error. Epidemiology, 23(5), 713-720.	Kuh, D., Ben-Shlomo, Y., Lynch, J., Hallqvist, J., & Power, C. (2003). Life course epidemiology. Journal of Epidemiology & Community Health, 57(10), 778-783.
Aliases	Sibling Comparison Design, Within-Family Fixed Effects, Discordant Sibling Design, Discordant Twin Design	Chain of Risk Model, Accumulation of Risk Model, Risk Chains, Additive vs Trigger Chains
Related	4	3
Summary	The sibling fixed-effects, or sibling-comparison, design controls for everything that siblings share by construction. Genes (on average half), parents, household income, neighborhood, schooling, and family culture are differenced out when you compare brothers or sisters who differ in an exposure, so the residual within-family association is purged of all confounders common to the family. D'Onofrio, Lahey, Turkheimer, and Lichtenstein championed these family-based quasi-experiments as a way to integrate genetic and social-science research by rigorously testing competing causal hypotheses. Frisell and colleagues, however, gave the design its essential warning label: precisely because shared confounding is removed, the within-family estimate is unusually vulnerable to the confounders siblings do not share and to attenuation from measurement error. The design is powerful but double-edged.	The chains-of-risk model is the specific life-course mechanism in which adverse exposures are linked in a sequence over time, so that one exposure raises the probability of the next, and the cumulative or final link bears on disease. Set out in Ben-Shlomo and Kuh's 2002 conceptual paper and defined in the Kuh, Ben-Shlomo, Lynch, Hallqvist, and Power 2003 life-course glossary, it models how early disadvantage can cascade — poor early circumstances leading to limited education, then to hazardous work or health behaviors, and finally to disease. Its signature analytic distinction is between an additive chain, in which each link independently adds to risk, and a trigger chain, in which the early links matter only because they lead to a final exposure that is the true cause. Chains-of-risk modeling thus treats the life course as a causal pathway to be decomposed, not a list of independent risk factors.