Reforming school finance systems to support performance standards entails estimating the cost of an adequate education. Cost of adequacy (COA) studies have been done in more than 30 states. Recently Eric Hanushek challenged the legitimacy of COA research, calling it alchemy and pseudoscience. The objectives of this study are to present reliability and validity criteria for evaluating the scientific merit of COA studies and to illustrate how they can be tested using cost function estimates for Kansas. Based on reliability and validity estimates for Kansas, Hanushek's blanket dismissal of all COA methods as unscientific seems unwarranted. However, he raised an important issue: Reliability and validity of COA estimates generally have not been demonstrated in published studies. To encourage more systematic evaluation of COA estimates, this research must move away from the advocacy environment to the realm of social science research, where methods can be tested and evaluated without pressure to produce only one answer. Funding of basic adequacy research should be by neutral parties, such as foundations or the federal government, not parties with a direct interest in the outcome. (Contains 7 tables, 1 figure, and 38 footnotes.)