One of the lowest performing school districts in the state has the highest average teacher salary in Northwest Indiana, a Times computer analysis shows.

But the average teacher salary also is directly related to the age of the staff, with older teachers having ascended to higher pay ranges, school officials say.

The Times review also shows that some of the highest performing schools -- including Munster and Valparaiso -- are among the top compensators of teachers in the region and that nine Lake and Porter county school districts compensate teachers at a rate above the state average.

During the 2007-08 school year, the highest average teacher salary anywhere in Lake or Porter counties was Gary, at $56,100. Indiana's average teacher salary was $48,484.

For the same school year, the average age of a Gary teacher was 53, the oldest average age for a teacher in Lake and Porter counties.

A Times computer-assisted analysis of three years of salary data showed Gary increased its teacher salaries by 7.06 percent -- the highest jump in the region from the 2005-06 school year to the 2007-08 school year.

Of the 23 school districts in Lake and Porter counties, four showed a decline in the average teacher salary -- Portage, Valparaiso, Lake Central and Hobart. Nine of the school districts paid teachers above the state average during that time.

While Gary paid the highest average salary in the region, the ISTEP-Plus scores have been among the lowest in the region and state. In the 2007-08 school year, 46.6 percent of all students passed the English portion of the test compared with the state average of 72 percent. Forty-seven percent of all Gary students passed the math portion of ISTEP compared with the state average of 74.6 percent.

Gary schools spokeswoman Sarita Stevens said there is no correlation between test performance and continued employment of teachers. She said teachers are tenured and licensed, with a legally binding collective bargaining agreement.

"We can't go in and say we consider you a nonperforming teacher and we're going to fire you," she said. "There are also many other factors that affect test scores, including the socioeconomic level of students, the poverty rate and a population that simply doesn't test well."

Valparaiso Superintendent Michael Benway said the older the staff, the higher the average salary. Benway's school district saw a decline of less than 1 percent over the three-year period.

"I expect that our average salary will get lower in the next couple of years because we're replacing about 25 teachers a year through attrition," he said. "We've got very mature teachers who are master teachers and very mature teachers who are younger -- and both are very good."

Rod Gardin, East Porter County schools superintendent, said the average salary also can be misleading because it doesn't include increment increases.

For example, he said teachers in his district received a 2 percent raise in 2007-08, but teachers who have between one and 20 years experience received another 3 percent in increments. Teachers who have more than 20 years experience don't get the increment raise, Gardin said.