Problems of epidemiologic method in assessing the type and extent of mental illness among homeless adults.

Because the problem of homelessness has generated such attention and controversy, findings from studies of homeless populations are often received eagerly without appreciation of the significant biases inherent in surveys. Drawing on surveys of the homeless made in the 1980s, the authors review problems in sampling and in measurement of mental disorder. They suggest that within any one study researchers employ alternative sampling strategies and measures of mental disorder to facilitate comparison of results within and across studies.