The purpose of this literature review is to study the advantages and limitations of various through-course summative assessment (TCSA) models with the goal of informing the design of the new and innovative adaptive through-year assessment system at NWEA. This system solution will measure each student's command of grade-level standards and academic growth, while also producing proficiency scores for accountability at the end of the school year--replacing the end-of-year state summative assessment. A primary motivator of this literature review is to study TCSAs and identify challenges they pose and to ensure that these challenges are taken into account in the design of the adaptive through-year assessment (ATYA). This literature review was guided by the following questions: (1) What is the definition of TCSA?; (2) What are the expected benefits of TCSA?; (3) What models have been proposed or discussed in the literature?; (a) What blueprint designs have been proposed by researchers?; (b) What statistical models have been proposed to combine scores from multiple interim scores into a single summative score?; (4) What are anticipated challenges and potential solutions to TCSA?; and (5) What are gaps in the literature on TCSA that need further research? This paper concludes by applying the findings of this literature review to the design of the ATYA, proposing a tentative design of the ATYA model from NWEA that addresses many of the challenges posed by TCSA.