Simulated amount of bias vs Type I error rate of the PG model with different levels of misspecification. The x axis represents the simulated amount of bias x = 2(100)(B-0.5) with B in the interval (0.35,0.65). The line labeled “0” represents the type I error rate TIER when q = (1 + 0%)B, the line labeled “1%” represents the TIER when q = (1 + 1%)B, and similarly for the lines labeled “2%”, “5%” and “10%”. Note that the smaller the simulated amount of bias is the lower B is and, therefore, the difference between B and the specified q, is smaller; hence the lower the TIER. This explains why the TIER increases with the simulated amount of bias. The horizontal line (grey) through 0.05 is shown for reference.