Jeff Donn, national investigative reporter, Boston, for his analysis of tens of thousands of health and safety inspections in a package that exposed for the first time a decade-long decline in living conditions for millions of poor tenants in federally subsidized housing. Donn’s mainbar, with dateline-specific reporting by Jackson, Mississippi-based investigative reporter Holbrook Mohr, told stories of tenants beset by cockroaches and leaks against a national backdrop of declining health and safety inspection scores. Vivid photography by Patrick Semansky in Baltimore and Rogelio Solis in Natchez, Mississippi, enhanced the package.