Prior to the No Child Left Behind (NCLB) Act, scientific research to support development of curriculum materials or to demonstrate curricular efficacy was not required. NCLB transformed the development and publishing process for K-12 educational materials by prompting publishers to increase funding for experimentally based research on educational products used in schools. To maintain a viable place in the market, textbook publishers have faced challenges such as difficulty in conducting experimental research in schools, coordination with states' proposed curriculum adoption cycles, and use of limited resources to meet the needs of many more stakeholders in the new accountability framework.