This sequential-explanatory mixed-methods study assessed the construct validity of the educative Teaching Performance Assessment's (edTPA) Elementary Education Literacy, Elementary Education Math, and Early Childhood assessment areas. The edTPA is a portfolio-based subject-specific teaching performance assessment developed by Stanford's Center for Assessment, Learning, and Equity (SCALE) and follows a 3-Factor model to assess constructs Planning, Instruction, and Assessment. The problem addressed in this study is that despite being a subject-specific assessment tool, factor structures for individual assessment areas are not reported in annual edTPA administrative reports. This gives rise to the possibility for individual assessment areas to be invalid without being realized. At the same time, teacher candidates who complete edTPA portfolios reportedly have experiences and perceptions which fail to align with what the edTPA purportedly measures, an issue that is exacerbated with 18 states mandating the edTPA for teacher licensure. Data were collected from a 4-year state university in the southeastern region of the United States. Quantitative data consisted of individual rubric scores from 2016-2019 for Elementary Education Literacy (n = 205), Elementary Education Math (n = 203), and Early Childhood (n = 40) assessment areas. Qualitative data consisted of nine interview transcripts from nine participants who completed edTPA portfolios during 2016-2019 in each of the three assessment areas. Confirmatory factor analysis and Cronbach's alpha were used to assess the construct validity and internal consistency of each of the three assessment areas as well as the internal consistency of rubric scores for each construct. Additionally, inductive analysis was used on interview transcripts to explore for emergent themes with the intent to supplement quantitative findings. Results indicated that construct validity for Elementary Education Literacy and Elementary Education Math was inconclusive, while Early Childhood did not have adequate construct validity. Internal consistency of scores for each of the three assessment areas was strong, whereas constructs Planning and Instruction did not satisfy the threshold for adequate internal consistency. Qualitative findings indicated that participants shared positive and negative perceptions of the edTPA, with the three most common themes across responses associating with Planning, Instruction, and Assessment being Disconnect, Heterogeneity, and Positive Aspects. Overall, the mixed findings from this study warrant further investigation and replication of factor analytic studies on individual assessment areas and exploration of teacher candidates' experiences focused on edTPA's constructs in order to better understand the edTPA's construct validity. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]