KANSAS CITY, Kan. — A pollster hired by Kansas Secretary of State Kris Kobach said Monday his survey of 500 Kansas adults found just one person who couldn’t produce a proof of citizenship document.

Pat McFerron, president of Cole Hargrave Snodgrass, also recognized possible bias and other concerns with his survey while under questioning from an attorney for the American Civil Liberties Union.

Monday is the seventh day in testimony in a federal bench trial over the state’s voter registration law. The trial is scheduled to conclude later Monday, followed by a contempt hearing for Kobach.

McFerron offered expert testimony over ACLU objections about not being identified as an expert witness before a deadline imposed by U.S. District Judge Julie Robinson. Sue Becker, chief legal counsel for Kobach’s office, offered conflicting explanations for her line of questioning, prompting Robinson to admonish Becker for “being schizophrenic.”

The judge allowed McFerron to testify, “even though defendants had violated the rules of civil procedure.”

Kobach paid McFerron, whose firm primarily serves Republican political candidates, $9,000 for his survey of Kansas adults. Nearly all said they could readily find their birth certificate or passport.

One of the survey questions asked: “In 2011, because of evidence that aliens were registering and voting in Kansas elections, the Kansas Legislature passed a law requiring that people who register to vote for the first time must prove that they are United States citizens before they can become registered. Do you support or oppose this?”

Seventy-seven percent supported the law, 14 percent opposed and 9 percent had no opinion.

ACLU attorney Neil Steiner pointed to the question and asked whether it introduces bias into the survey. McFerron agreed it could.

Steiner made light of McFerron’s failure to complete a graduate degree, then needled him later with a reference to another witness who has a PhD. McFerron wasn’t aware of academic research about polling methods and didn’t account for the concept of “social desirability,” in which survey respondents offer inaccurate answers they think will make them look good.

Of the 500 people surveyed, 83 percent already were registered to vote in Kansas. Steiner questioned the value of talking to people who wouldn’t be subjected to a law requiring new voters to show proof of citizenship.

“You can’t tell this court anything about the impact of the voter registration law on people who are not already registered to vote in Kansas,” Steiner said.

If the trial concludes as scheduled, a contempt of court hearing for Kobach will follow Monday afternoon or Tuesday morning. ACLU contends he didn’t follow the court’s orders to help register voters while waiting for this case to be resolved.