Tucson's status as a college town does not explain its relatively high poverty rate - but it does impact it.

If college students living off campus were excluded from the city's population in poverty measurements, the rate would appear slightly lower.

Pima County's poverty rate would drop 1.3 percentage points, and Tucson's would fall by 2 percentage points, the U.S. Census Bureau reports.

The figures are calculated using a sample of data collected by the American Community Survey from 2009 to 2011. In the recalculated rate, students between the ages of 18 and 29 who were living off campus but not with relatives are exempted.

Tallied that way, Pima County's poverty rate would be 18.1 percent and Tucson's would be 23.3 percent.

The declines, while small, are statistically significant at a 90 percent confidence level.

The bureau recently released the alternative poverty rates for states, counties and some municipalities because it had received repeated inquiries about students' impact.

It already had some experience with the revisions. Tompkins County, New York, where Cornell University is located, had contracted with the bureau to quantify students' impact on its decennial poverty rate.

There, the calculation change dramatically changes the picture. The county's poverty rate drops from 21 percent to 11.5 percent.

Nationwide, about one-quarter of college students live off campus but not with family. More than half of them have incomes below the poverty level.

Contact reporter Carli Brosseau at cbrosseau@azstarnet.com or 573-4197. On Twitter: @carlibrosseau