Federal data released this week shows that the percentage of students who graduate high school in four years is at a level not seen since 1974.

The National Center for Educational Statistics reported that a federal average of 78.2 percent of students graduated in four years. Georgia is ranked 45th in the nation, with 69.9 percent of students graduating on time.

Locally, both the Carrollton City and Carroll County school systems have done better than the state.

The cohort graduation rate — meaning the percentage of students who graduate four years after entering high school — at the county system is 75.8 percent. In the city school system, that figure is 82.7 percent.

Although the state is ranked 45th in the nation, Georgia has improved steadily since 2002, when 60.8 percent of students graduated in four years.

The state with the worst reported graduation rate is Nevada, with 57.8 percent of students graduating in four years. The state with the best graduation rate is Vermont with 91.4 percent.

The local superintendents have previously expressed mixed opinions about the new method of calculating graduation rates, with students who do not graduate in four years not being counted toward the rate.

“I have mixed opinions on it,” Carroll County Schools Superintendent Scott Cowart said. “But I applaud what they’re trying to do, which is create a consistent platform.”

Carrollton City Schools Superintendent Dr. Kent Edwards said he is supportive of the new calculation, but difficulties arise anytime a student transfers.

“I think it’s suitable for everyone to be on a similar scale,” he said. “It just creates some problems whenever we have transient students.”

The state average fell 13.5 percent with the new calculation, landing at 67.4 percent for the cohort rate from the former leaver-rate 80.9 percent.

Schools in Carroll County were not affected as harshly as the state average — Carrollton High School’s rate dropped only 3.31 percent, while the average of the high schools in Carroll County Schools dropped 8.478 percent.

State and local officials stressed that this does not represent a loss in the number of graduates, only a change in the data used to measure the rate.

“I think it’s important to make sure we’re comparing apples to apples,” Cowart said. “The calculations are not similar. They’re changing the numerator and the denominator of the formula, so comparing the two would be like comparing apples to oranges.”

According to the Department of Education, cohort data was implemented this year after Gov. Nathan Deal and the nation’s 49 other governors agreed to participate in a common calculation method for graduation rates.

Both the Carroll County and Carrollton City school systems have targeted the graduation rate as a point of focus in recent years, and as a result, developed several initiatives in collaboration with local businesses and members of the community that are aimed at keeping dropout numbers low.

Among these are Carroll County Schools’ partnership with Southwire Company in 12 for Life, which is in the middle of its sixth year of offering at-risk high school students an opportunity to earn a paycheck along with high school credit; the Carrollton City Schools’ Performance Learning Center, which provides an alternative learning environment for some students starting last fall; and dual system work on Communities in Schools, a nonprofit organization charged with gathering community support for students as they progress through school.

“Most systems have identified initiatives and strategies to target the dropout rate,” Edwards said. “And the programs we’ve put into place are meant to be remedial opportunities missed in the school day. We have opportunities after school that are not being utilized.”

Edwards said the system’s PLC will be particularly helpful because it will provide a place of student intervention without being an alternative school.

“The PLC is something for students looking for a non-behavioral structure to address students who need help and more one-on-one instruction that’s not in an IEP (individualized educational program) setting,” Edwards said.

The Georgia Department of Education’s data for the 2010-2011 cohort graduate rate, 2010-2011 leaver rate and the percentage point decrease between them for the local school systems:

Temple High: 78.8 percent, 85.8 percent, 7 percent

Mt. Zion High: 76.8 percent, 87.7 percent, 10.9 percent

Central High: 75 percent, 78.9 percent, 3.9 percent

Bowdon High: 79.5 percent, 86.1 percent, 6.6 percent

Villa Rica High: 68.9 percent, 83 percent, 14.1 percent

Carroll County Schools averages: 75.8 percent, 84.3 percent, 8.5 percent

Carrollton High: 82.7 percent, 86 percent, 3.3 percent