1. Introduction: Human capital refers to the set of skills, knowledge and personality attributes embodied in the ability to perform work in a way that produces economic value. They are the attributes acquired by a worker through education and experience, according to Sullivan and Sheffrin (2003). An increase in the level of education improves the skills and increases the knowledge necessary for a population to operate efficiently and productively. It is a widespread belief throughout the world that the more productive the workforce, the more prosperous the economy will be; therefore, there is huge public investment in education in both developed and developing countries. The common belief raises a general question: does an increase in investment in education necessarily improve educational outcomes? This article focuses specifically on testing the correlation between public education spending and student academic performance in Washington State within the K-12 education system with a least squares regression. To answer the question, it is necessary to consider education as an economic good, because education is not easily obtainable and therefore must be shared, as stated by Olaniyan and Okemkinde (2008). Like other investment goods, education has a supply function where government spending on education is an input and its output is the academic performance of students. Due to the positive externalities of education, a society would benefit from the educated population as human capital and a driving force of technological progress. However, excessive spending on education is a waste for both families and society, so it is important to derive the precise relationship between education spending and students' academic performance, and thus maximize the return on education based... middle of paper ......Scientific research.6. Hanushek, Erick.2007. Educational production functions. Hoover Institution, Stanford University.7. Startz, Dick. 2010. Introduction. Profit from education. Santa Barbara, California: Praeger.Pritchett, Lant, and Deon Filmer. 1997. What Educational Production Functions Really Show: A Positive Theory of Educational Spending.8. Taber, Christopher. 2009. Production functions of education. University of Wisconsin. www.ssc.wisc.edu/~ctaber/751/edpf.pdf9. Levin, Henry.1994. Increase educational production. Stanford University.10.Berliner, David C. and Bruce J. Biddle. 1995. The Manmade Crisis: Myths, Fraud, and the Attack on American Public Schools. Redding, MA: Addison-Wesley Publishing Company.11. Bishop, John and Ludger Woesmann. 2001. Institutional effects in a simple model of educational production. Faculty Qualifications-Human Resources Studies