lines thus having redshift limitations and spectroscopy is an expensive use of telescope time). To examine the extent to which the samples we consider in this paper suffer from different selection effects we therefore employ a cumulative distribution plot with a manual weighting for each population so as to scale the populations to an arbitrary level at a designated redshift. In this work, we will adopt [*z*]{} of 2.5 for such a designated redshift as it is the approximate end of the redshift range for which we have metallicity measurements. For populations that do not reach the designated redshift we scale the weighting to achieve the best congruence with the other populations. We also adjust the weightings of all the populations as needed to favor a common congruence.

This is a manual process, as the goal is to produce a distribution plot where deviation of congruence is reflective of redshift dependent selection biases. While a program to estimate a scaling values that minimizes the area between two curves could be used instead, the advantage of doing the scaling by hand it that when the samples agree to a point and then diverge this can be shown in a physically meaningful 