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. 2022 Sep 20;6(10):e10675. doi: 10.1002/jbm4.10675

Fig. 1.

Fig. 1

The three core assumptions of Mendelian randomization. Red dashed arrows represent pathways that should not exist if the instrument is valid. Blue arrows represent conditions that need to be true for an instrument to be considered valid. The black dotted arrow represents the fact that the confounder does not need to influence the exposure to violate instrumental variable 2 (IV2): the assumption is no confounding of the genetic instrument and the outcome.