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Instrumental Variable (IV)

Definition
AI-generated

An instrumental variable is a variable associated with an exposure, independent of the unmeasured confounders of the exposure-outcome relationship, and affecting the outcome only through the exposure.

Topics
Post-GWAS
Related
GWAS Summary Statistics Horizontal Pleiotropy (MR) Linkage Disequilibrium (LD)

Why it matters in GWAS

The instrumental-variable assumptions are the core identification conditions behind Mendelian randomization. Weak instruments, linkage disequilibrium, or horizontal pleiotropy can bias causal estimates even when the GWAS summary statistics themselves are well powered.

Example usage

"Instrumental Variable (IV) is referenced when translating statistical signals into biological context."

GWAS Summary Statistics Horizontal Pleiotropy (MR) Linkage Disequilibrium (LD) Mendelian Randomization (MR) TwoSampleMR Vertical Pleiotropy
Related-term network

Click any node to open that term page.

Node order. The current term is first. Next come every page linked from Related terms, in the same top-to-bottom order as that list. Then new terms appear in two-hop layers: for each of those direct neighbors (in that same order), their related terms are appended if not already listed. A third pass does the same for two-hop nodes. The walk stops when a fixed maximum number of nodes is reached.

References

  • Davey Smith G, Ebrahim S. (2003). Mendelian randomization: can genetic epidemiology contribute to understanding environmental determinants of disease? Int J Epidemiol.
  • GWASTutorial: Mendelian randomization.
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