Bias and variance results (values within parentheses) of MR-PL and other MR approaches in baseline simulation.

Bias was calculated as the mean of the absolute difference between causal estimate and true effect, and variance was calculated as the variance of causal estimate minus true effect (averaged across 100 replications for each setting). The lowest value is highlighted in bold in each scenario, and the second lowest value is highlighted in underline. (XLSX)