By Cherri Gregg

HARRISBURG, Pa. (CBS) — On Day Two of the hearing over Pennsylvania’s voter ID law (see related stories), an elections expert has testified that the number of people affected by the new law could be substantially larger than the Commonwealth acknowledges.

A big part of the court fight has been over the number of voters impacted.  State figures on voters with no acceptable ID have varied from 90,000 to a quarter of a million.  But plaintiffs claim that figure is even higher.

Today, University of Washington professor Matt Barreto, a voting and elections expert, began testimony for the voter challengers, arguing that the number is likely much higher than the state admits.

He conducted a survey of more than 2,000 eligible Pennsylvania voters (both registered and unregistered) to see how many actually have proper ID.   According to his report, more than 14 percent of eligible voters and 12 percent of registered voters — that’s more than 1.3 million people — could be turned away at the polls.

He also produced figures that show that women, minorities and those with lower income are less likely to have proper ID for voting.

Barreto testified that the state’s comparison of voter rolls to the Penndot ID database is not an accurate way of determining who has an ID.

The state was expected to cross-examine Barreto this afternoon.