The purpose of this study was to evaluate decision making in the Common Core State Standards Initiative as the change process moved from research, development and diffusion activities to adoption of the Common Core State Standards by the states. A decision-oriented evaluation model was used to describe the four stages of planning, structuring, implementing and recycling decisions in the Common Core State Standards Initiative. Content analysis and survey methods were used to analyse literature referring to the Common Core State Standards and to obtain verification of information reported on the Common Core State Standards from officials of national organisations and state education agencies. The results showed that planning, structuring and implementing decisions were effective in producing Common Core State Standards that satisfied the expectations of most stakeholders, but recycling decisions needed to modify the Common Core State Standards Initiative remain unresolved. Awareness about a lack of agreement between what standards-based education is intended to be and what it actually is led policy makers to determine that common standards offered a solution to this problem. The setting for decision making in attaining this solution involved attempting a large change supported by a low understanding of how to accomplish the change. This setting required the National Governors Association Center for Best Practices and the Council of Chief State School Officers to design an action plan for programming the segments of research, development, diffusion and adoption of the Common Core State Standards in advance. Decisions about the extent, to which the desired ends of the Common Core State Standards Initiative have been attained, have focused attention on determining a new governance structure. All of the states, except for Alaska and Texas, joined the Common Core State Standards Initiative by signing a memorandum of agreement. By July 2011, all of the participating states, except for Montana, Nebraska and Virginia, had adopted the Common Core State Standards formally or provisionally. State profiles for each of these states describe the process of adoption and implementation of the Common Core State Standards by referring to plans for teacher development, curriculum alignment, instructional materials selection, assessment alignment, and accountability systems design. The results showed that effective decision making in planning, structuring and implementing the Common Core State Standards Initiative led most of the participating states to adopt the Common Core State Standards readily, and to initiate plans for implementation by aligning state standards and curriculum to the Common Core State Standards and to provide professional development for educators. (Contains 2 tables.)