MR using a Robust Adjusted Profile Score (MR-RAPS)

This method maximises the profile likelihood of the Wald ratio (or ratio estimates), accounting for weak instrument bias, pleiotropy and extreme outliers. 

All single nucleotide polymorphisms (SNPs) being used as instrumental variables (IVs) can be invalid due to pleiotropy as long as the pleiotropy is balanced. 

References

• Zhao Q WJ, Hemani G, Bowden J, Small DS. Statistical inference in two-sample summary-data Mendelian randomization using robust adjusted profile score. arXiv 2018.

Other terms in 'Weak instrument-robust two-sample MR methods':

• Adjustment of the NO Measurement Error (NOME) assumption
• debiased IVW
• Genome-wide mR Analysis under Pervasive PLEiotropy (MR-GRAPPLE)
• mrAR
• Three-sample MR