US Secretary of Education Arne Duncan says a longer school day in Chicago is a no-brainer.

The secretary was in Chicago on Friday as part of a national bus tour to promote state education reform. Duncan spoke on a panel with Chicago Mayor Rahm Emanuel, Illinois Governor Pat Quinn on the last stop of his trip.

Duncan told reporters he wishes he could have made the school day longer when he was the CEO of Chicago Public Schools, as it is “hugely important.”

“To have Chicago have the shortest school day and the shortest school year amongst other big city urban districts, that’s not a badge of honor. That’s something we should be ashamed of,” Duncan said. 

The Chicago Teachers Union has said it’s concerned about the quality of a longer school day. The union has said CPS could be violating union contracts by negotiating directly with teachers and has filed legal action against the school district.

Mayor Rahm Emanuel said there isn’t any problem with individual schools voting for a longer school day.

“I think it’s empowering parents, empowering children, and empowering teachers, since the teachers are taking the vote. They have the process to make that decision as is defined in the contract. This is exactly following the contract as drafted,” Emanuel said.

Emanuel has offered financial incentives to schools and teachers to lengthen the day, and five schools have agreed to work outside the union to do it thus far.