"The U.S. Department of Housing and Urban Development's (HUD's) Office of Policy Development and Research (PD&R) supports the Department's efforts to help create cohesive, economically healthy communities.
"PD&R is responsible for maintaining current information on housing needs, market conditions, and existing programs, as well as conducting research on priority housing and community development issues. The Office provides reliable and objective data and analysis to help inform policy decisions. PD&R is committed to involving a greater diversity of perspectives, methods, and researchers in HUD research."
And that's where I found Qualified Census Tracts and Difficult Development Areas and other low-income data regarding housing, which can be applied to other uses.