Published studies of intervention effects probably report effect sizes that are larger than the true effect size. There are probably many reasons for this, but one can be thought of as a "winner's curse." In this essay, I discuss evidence from two recent studies that highlight how evidence clearinghouses might inadvertently expose themselves to the winner's curse, describe reasonable and unreasonable expectations for evidence clearinghouses, then suggest strategies clearinghouses might adopt to reduce their exposure to the winner's curse.