This article examines the statistical precision of cluster randomized trials (CRTs) funded by the Institute of Education Sciences (IES). Specifically, it compares the total number of clusters randomized and the minimum detectable effect size (MDES) of two sets of studies, those funded in the early years of IES (2002-2004) and those funded in the recent years (2011-2013). Overall, the average precision in terms of MDES of studies in the recent cohort was more than double that of the early cohort (i.e. 0.48 compared to 0.23). The findings suggest a consistent and substantial increase in the precision of CRTs funded by IES in the past decade which is a critical step towards designing studies that have the potential to yield high-quality evidence about the effectiveness of educational interventions.