The Effective Health Care program at the Agency for Healthcare Research and Quality (AHRQ) sponsors the development of evidence reports and technology assessments to assist public- and private-sector organizations in their efforts to improve the quality of health care in the United States. The program represents an important Federal effort to compare alternative treatments for health conditions and make the findings public. The program is intended to help patients, doctors, nurses, pharmacists and others choose the most effective treatments. For this report, researchers at the Vanderbilt Evidence-based Practice Center in Nashville, TN, conducted comparative effectiveness research on treatments for autism spectrum disorders in children ages 12 and under. Treatments included behavioral, educational, medical, allied health, and complementary and alternative medicine interventions.