Pearson Education contracted with Empirical Education Inc. to conduct five randomized experiments to determine the effectiveness of its "Scott Foresman Science" ("SFScience") curriculum and associated materials. This report addresses the experiment in Federal Way Public Schools in Washington State. The primary purpose of this research is to produce scientifically based evidence of the comparative effectiveness of the "Scott Foresman Science" program. The question being addressed by the research is whether the "SFScience" is more effective than the current curriculum being used by the participating campuses in the Federal Way Public Schools District. The research focuses on 3rd, 4th, and 5th grade students. The outcomes were measured by student achievement on standardized tests administered at the beginning and end of the project. Two test areas were selected as the outcome measures: (1) the Northwest Evaluation Association's Science Concepts and Processes; and (2) Reading Achievement assessments. The design of the experiment reflects the requirements of the No Child Left Behind Act, which directs schools to consult reports of rigorous research in making adoption decisions about instructional programs. A randomized experiment such as the authors have conducted provides a rigorous test of the program because it removes sources of bias. In particular, the authors reduce selection bias by tossing a coin to assign teachers to use a program--in this case, "Scott Foresman Science"--or to continue using their current teaching materials and methods. Random assignment to experimental conditions does not, however, assure that the information can be generalized to support local decisions that take into account the specifics of district characteristics and their implementation of the program. The results should not be considered to apply to school districts with practices and populations different from those in this experiment. This report provides a rich description of the conditions of implementation in order to assist the district in strengthening its program and to provide the reader with an understanding of the context for the findings. (Contains 36 tables, 8 figures and 5 footnotes.) [Funding for this paper was provided by Scott Foresman.]