First, it is important to note that throughout this arti- cle, we distinguish between what we call “intended power” and “actual power.” Intended power is the ideal- ized benchmark set by the researcher, often .80 or .90. Researchers often incorrectly assume that the power they have achieved will equal their intended power as long as they collect data from the planned number of partic- ipants. In contrast, actual power is the probability that the true effect in question will be detected, given the popula- tion effect size parameter. However, the magnitude of the true effect to be detected in replication studies is unknown and is typically estimated from the sample effect size in the original study. If there is a difference between the esti- mated effect size of the original study and the population effect size of the phenomenon of interest, then there will be a difference between the actual and intended power in the replication study. Neither the extent of the difference between intended and actual power in replication studies nor the effectiveness of possible strategies to reduce this gap has been systematically studied.