Finally, we take a closer look at bulk fitness measurements -even under perfect measurement there is room for discrepancy because of different choices for the reference group and higher-order effects. We recommend inoculating the mutant library at ~25% of the initial biomass, and include wild-type.

Why care about the choice of fitness statistic? As microbial ecologist, we naturally care about reliable physical equipment to get the best data out of the labor. I argue, we should apply the same high standards to the relative fitness statistics that we use to quantify these experimental data. n/n