The Housing Assistance Supply Experiment surveyed all neighborhoods in St. Joseph County, Indiana (Site II), between September 1974 and December 1975. The survey consisted of two distinct instruments--one for neighborhood street observation (the NSOB), the other for surveying neighborhood local sources (the NLS). The NSOB recorded the presence or absence of various land uses and rated the quality of residential buildings, public streets, and vacant land. The NLS collected data on access to public facilities, characteristics of streets and highways, air pollution, and school and crime statistics. The audit determined that NSOB data are exceptionally complete and that averaging the quality rating questions should produce useful analytic variables. Few errors were detected in NLS data; however, fieldworkers used questionable procedures for estimating public service coverage and were imprecise in measuring acreage for different soil groups and flood hazard areas.