Systematic assessments of neighborhood physical environment were conducted by trained independent observers in a random sample of 138 block groups in all the 54 Detroit neighborhoods. Observers rated the neighborhood physical environment on 19 items adapted from the New York City IMPACT neighborhood evaluation scale.43 Factor analyses suggested that three items formed a cohesive measure of the external physical environment, which are as follows: (1) presence of buildings with broken windows; boarded-up windows or boarded-up doors; (2) presence of buildings with outside damage that can only be corrected by major repairs such as siding, shingles, boards, brick, concrete and stucco and (3) presence of entirely vacant buildings. These measures also demonstrated excellent internal consistency (α=0.83). The factor analyses yielded principal component values for each block group, which were detailed previously.28 Frequency values were predicted for those areas of Detroit that were not evaluated and maps of these prediction estimates were created. Predicted values were then averaged by neighborhood so that a higher score indicates more physical disorders.
