“…We have highlighted the detrimental effects of measurement error in the outcome when planning multilevel experiments, extended the tools available to efficiently plan these experiments, and provided additional recommendations to improve evaluation planning but recognize the vast scope of multilevel experimental designs and the current extensions of the optimal sample allocation framework far exceed what is discussed here. For instance, subsequent work should consider how measurement error influences experimental design when probing moderation and mediation effects (e.g., Kelcey, Dong, Spybrook, & Cox, 2017; Kelcey, Dong, Spybrook, & Shen, 2017; Kelcey et al, 2019; Spybrook, Kelcey, & Dong, 2016). We also encourage future work to expand considerations of measurement error into other designs such as three- and four-level CRTs and multisite CRTs.…”