The methodology used in the HUD computer program blends together Family Income data with Unrelated Individual Income data. It was determined not to use household income data because it is not directly comparable with Metropolitan Statistical Area (MSA - formerly called SMSA) income levels or with Section 8 Income limits, both of which are derived from Family Income and Unrelated Individual Income data. The methodology is as follows:

The average persons per family for each Block Group or Census Tract multiplied by the number of lower income families to get lower income persons in families.

The low mod persons in families is then added to the number of lower income unrelated individuals to get the total lower income persons in the Block Group or Census Tract.

The total persons in families is added to the total unrelated individuals in the unrelated individuals income distribution to get the total persons in the Block Group or Census Tract.