Methodological rigor in intervention research is important for documenting evidence-based practices and has been a recent focus in legislation, including the No Child Left Behind Act. The current study examined the methodological rigor of intervention research in four school psychology journals since the 1960s. Intervention research has increased in prevalence, but it does not seem to have become more rigorous since the establishment of the What Works Clearinghouse. Small methodological factors often determined whether a study met or did not meet standards in the current investigation. Implications include the necessity of reviewing research quality guidelines prior to conducting intervention research and ensuring they are met whenever possible. (Contains 5 tables.)