Significant growth and improvement of school mental health programs has occ
urred in recent years. However, evaluation of outcomes for children receivi
ng these services is needed to provide accountability data and ensure the s
ustainability of these programs. When designing studies, evaluators must ov
ercome several challenges that may threaten the validity of their conclusio
ns. In this paper, threats or challenges to the internal and external valid
ity of results from evaluation studies are reviewed. Suggestions are provid
ed for overcoming these challenges, in order to encourage future evaluation
activities in this developing field and to document the impact of services
for services for youth and their families.