CWLA is the "oldest and largest national nonprofit organization developing and promoting policies and programs to protect children and strengthen families." Good resources under Research/Data.
The mission of the Data Resource Center (DRC) is to take the voices of parents, gathered through the National Survey of Children’s Health (NSCH) and the National Survey of Children with Special Health Care Needs (NS-CSHCN), and share the results through this free online resource.
“Provides an introduction to key issues as well as in-depth information on poverty measurement, monitoring, analysis, and on poverty reduction strategies for researchers and practitioners.” Includes an online Library.