Fig. 1

Simulation of the effects estimation influenced by none or two confounder effects. On the y-axis, the percentage deviation from the predefined \(\Delta _{Beta}\) to estimated \(\hat{\Delta }_{Beta}\) and on the x-axis the raw mean difference of the Beta-values between treatment groups. The first subplot shows the 0% confounder effect. The other two subplot the confounder effects of 10% and 20%. Simulated data with two treatment levels. The deviation is not symmetrical, because the confounder effects were always simulated in the same direction. 5000 simulations with \(n=1000\) each