There are many thousands of organizations in the U.S. (and internationally) that provide research on public policy issues. Types include:
Your challenge is to think critically about these sources, identify potential biases, use them to identify additional research, and generally separate the wheat from the chaff.
When searching, use topical terms: (not "psychological development," but "aspergers syndrome" or "children AND homelessness" or "older people AND cognition").
