To improve the quality of research and commentary concerning adolescent sexuality and evaluation of both comprehensive sexuality education and abstinence education programs, this article aims to help readers (1) select appropriate measures to study adolescent sexual behavior, (2) develop appropriate study designs to evaluate adolescent sexual health behavior intervention outcomes, and (3) interpret study results. Examples of measures that have been used in studies are identified. Suggestions are made as to measures that may be better choices. Additionally, different types of designs are highlighted and discussed. Instances in which reports and published articles have incorrectly interpreted the results of research studies are presented.