Cook County Assessor Joseph Berrios on Tuesday defended his office’s methods for evaluating property taxes, in the face of scathing criticism that the system is unfair to poor and minority areas.

Berrios faced tough questioning Tuesday before Cook County Commissioners, who called on him to testify in response to a recent Chicago Tribune investigation that found the assessor’s methods for evaluating property values is “fundamentally flawed,” and ends up favoring wealthier, whiter communities while charging higher effective tax rates to people who live in poorer areas.

Berrios has disputed the newspaper’s findings, saying they’re “not sufficiently credible.” And he defended himself to commissioners again on Tuesday.

“No mass appraisal system is exact but we our always looking for ways to make improvements,” Berrios testified.

Berrios, who is also the chairman of the Cook County Democratic Party, said he grew up in the Cabrini Green housing project and was one of the first Hispanics elected to countywide office.

Berrios said he would not allow minorities to be treated unfairly.

“I stand for equality in everything I do. We want people to know that the appeal process is open and transparent for everyone,” Berrios said.

Cook County Commissioner Jesus “Chuy” Garcia, D-Chicago, specifically summoned Berrios to testify before the board to answer whether the system is unfair to minorities.

“The questions raised are very, very concerning. These are people who work hard to make ends meet and hold on to the little bit that they have especially if they decided to own a home,” Garcia said. “Are poor people getting shafted in the Chicagoland community?”

Berrios responded that his office strives to get assessments right in Cook County.

“I’m not looking to say the system is infallible or the system is 100 percent correct. The system will never be at 100 percent,” he said.

Using charts and graphs, Berrios and his staff spent more than three hours explaining the county’s complex system of assessing property taxes. Berrios said assessments are determined by a number of factors, including state law, that are beyond his control.

It wasn’t only county commissioners who questioned Cook County’s assessment system. Christopher Berry, a professor of public policy at the University of Chicago, said the system is “neither fair nor accurate.”

“If the system was fair and accurate, homes would be priced all at the same ratio regardless of their value.”

But homes in largely minority neighborhoods, Berry claims, are assessed at 8.6 percent of a home’s value, while those in white neighborhoods are assessed at 10 percent.

“I’m not saying that Joe Berrios or anybody on his staff is racist,” Berry said. “I am saying, and the data clearly support, that the assessment system we have produces racially discriminatory assessments and taxes.”

Commissioner Richard Boykin, D-Forest Park, said property owners should have confidence in the system.

“Taxpayers need to have a certainty that they are not being over-assessed or over-valued,” Boykin said. “We have to need to make sure that everybody is treated fairly.”

Following the meeting, Democratic Board President Tony Preckwinkle announced that she has commissioned a full review of the county property tax system from the Civic Consulting Alliance.