The purpose of the first study was to develop and validate a new self-report survey used to determine the level of agentic, behavioral, cognitive, and emotional engagement of eighth and ninth grade boys and girls in physical education. Much of the development was driven by work completed by Reeve and Tseng (2011), and by Reeve (2013). Two hundred thirty-one surveys were administered to eighth and ninth grade boys and girls, and 220 surveys were included in the analysis. Results from the confirmatory factor analysis (CFA) were used to determine the goodness of fit showed good factor structure and all of the fit indices (X[superscript 2]/df, GFI, CFI, NFI, SRMR, & RMSEA) met a good to an acceptable level. Of the original 21 items in the scale, 18 items were part of the final model. The final model showed to have an expectedly high correlation between agentic and cognitive engagement which have an impact on the discriminant validity of the structure. The purpose of the second study was to design a reliable observation instrument and validate that instrument. The expressed intent of this instrument was to measure student engagement levels in physical education and to create a dependent variable that could be used by teachers and researchers. Semi-Structured interviews with 20 experts in the field of physical education were conducted to create an operational definition of the term engagement. Experts were asked questions about targeted students in 11 physical education lesson video clips that lasted between 15 and 40 seconds and the descriptions given were analyzed for frequency of use. These descriptive words were then used as the basis for the observation instrument and the criteria for proper coding of the behavior of the targeted students. Inter-rater reliability percentages were high for all of the attempts and the determination that the instrument could be used effectively in the field. A training manual with coding conventions was also created to allow new users the opportunity to become efficient and effective observers when using the observation tool in the field. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]