On the first day of school this year, Utah schools were 173 teachers short. That's 25 percent more missing teachers than on the first day of school last year, according to the report by University of Utah professor David Sperry.

Also, Utah colleges and universities trained about 1,200 fewer teachers than schools needed this year. About 34 percent of teachers hired this year came from Utah colleges and universities. The rest came from outside the state, alternative certification programs and other school districts, among other places.

Gov. Jon Huntsman Jr. said the teacher shortage has to end for the sake of Utah students.

"It's the most important issue we can work on," Huntsman said at his annual Governor's Education Summit. "If we can't succeed in filling the slots for teachers, nothing else works."

Generally, the numbers haven't improved since Sperry's last much-talked-about report on the shortage, in 2005-06. Since then, legislators and state leaders have implemented raises and discussed other ideas about compensation and training, but the shortage persists because such improvements take time, state schools Superintendent Patti Harrington said.

The study blamed the shortage largely on a growing number of students and teacher attrition. More than 11 percent of teachers left their jobs after last school year, and most of those teachers - about 55 percent - had been teaching for five years or fewer when they left. The biggest reasons teachers left their jobs last school year were to retire, for personal/family issues or because their spouses were relocating.

Rob Smith, Alpine School District chief financial officer, said his district is still about 15 teachers short, mostly in special education. Shortages can lead to larger class sizes and less individual attention, he said. Alpine had 15 percent turnover - or 399 teachers who left the district - last school year, according to the report.

The report recommended Utah give more resources to state colleges and universities to better recruit and train teaching students; try to reduce teacher attrition through better pay, better working conditions and mentoring programs; and attract more teachers through pay and/or creative scheduling.

They're suggestions that are already in the works, state leaders said. Huntsman said his education priority this legislative session will be to improve teacher pay. He said he would like to see teachers' salaries boosted to more than $40,000 by 2012. Beginning teacher salaries in Utah are now about $31,000, he said.

Huntsman said his budget recommendations to the Legislature will reflect that priority.

Rep. Ronda Menlove, R-Garland, an educator, said the state school board and a legislative subcommittee on the shortage have been studying differentiated pay for teachers who fill critical spots and extended school years and/or days, among other things.