Fig. 9

Kernel density estimation (KDE) plots for selected risk of bias characteristics. Pink represents the distribution of all effect sizes. Teal represents the distribution of effect sizes with “low” or “unclear” risk of bias rating for each characteristic. KDE plots are shown for the four stressor-response relationships. Abbreviations correspond to the study validity assessment characteristics in Table 2 as follows: pairing of nutrient and chl-a measurements = pairing nutrient response; site-based temporal replicates  = within-site replicates; randomization of sampling (selection bias) = randomization