The What Works Clearinghouse (WWC) was established by Institute of Education Sciences to summarize the research evidence on curricular programs. Yet, WWC conclusions differ dramatically from those found in reviews and meta-analyses in the scholarly literature, and involve data from only a small portion of the available evidence. An article written by NIFDI Research staff and published in the American Journal of Evaluation explains why these discrepancies occur. An op-ed piece describing the conclusions and a link to a free download of the article can be found here.