"The poverty threshold does not vary by state, even though the cost of living in each state is very different. However, each year's poverty threshold is updated by taking last year's poverty threshold and adjusting for inflation, using the consumer price index."

Poverty Threshold

This part might be skewing the poverty level. Everyone could be poor except for a single family member, but they won't count :"The poverty threshold measurement is an all-or-nothing proposition. If the total family income is below the threshold, then everyone in the family is poor. If the income is greater than the threshold, then no one in the family is poor."