Nearly eight years after Shiloh became the first Gwinnett high school to employ what was billed as a revolutionary way to restructure the school day, school leaders are abandoning the concept.

Next school year will be the last that Shiloh students take four 90-minute classes a semester, a class schedule called "block scheduling." In August 2008, Shiloh students will start following the traditional set-up used at most Gwinnett high schools.

The traditional high school day contains six class periods, each lasting about 55 minutes. Students typically take the same classes all year. The design currently used at Shiloh, called a "4x4" block schedule, divides the school day into four 90-minute periods. Students typically take different classes each semester.

During the 1990s, block scheduling was the hot education fad. While it didn't become as popular in Gwinnett County, thousands of high schools across the nation adopted block schedules. About half of all Georgia high schools now use block schedules.

Shiloh Principal Gwen Tatum said her school will stop using a block schedule because of a loss of class time. Students spend about 30 fewer hours of classroom time on a subject when using a block schedule rather than the traditional schedule. While a block class lasts about 90 minutes, it meets only half a year, thereby reducing the number of hours teachers spend on each subject.

"This loss of learning time isn't working for our kids," Tatum said. "It's time to move on. We have to realize that what worked for the students we had in 1999 doesn't work for the students we have now."

But the block schedule won't vanish from Gwinnett. Peachtree Ridge has used a block schedule since the school opened in 2003 and plans to continue, Principal Steve Flynt said.

"Really, I don't believe it is just the scheduling program that makes a school," Flynt said. "I think you can have high academic achievement no matter what your program is."

The design remains popular across metro Atlanta. Twelve of the 15 high schools in the Cobb County district use it. So do 19 of the 21 high schools in the DeKalb County district. Three of Fulton County's 12 high schools use a block schedule, but two will switch to a more traditional schedule in August, a district spokeswoman said.

Through block scheduling, students take eight courses a year instead of six, providing more time for electives or to make up classes students failed the previous semester. The schedule also allows students to focus on two electives and two academic subjects, so they can balance the hardest courses with easier ones.

The 90-minute class gives teachers more time for hands-on projects, such as science experiments. Teachers also have time to review homework and concepts that stumped students.

Some Shiloh students, such

as sophomore Morgan Whel-chel, said the block schedule makes high school easier. "I like having only four classes to focus on instead of six and our teachers have more time to answer our questions," Morgan said.

There was little research about the program when Shiloh implemented it in August 1999. But a two-year analysis of test scores by the state Department of Education released in 2005 found that Georgia students at block-schedule schools scored lower on key tests, including the SAT and state graduation exam, than students at high schools with a traditional schedule.

Critics also complain that the block schedule sometimes forces students to wait too long before taking next-level classes in sequential courses. For example, a student may take Spanish I during the first semester of freshman year, but not take Spanish II until the second semester of sophomore year.

Flynt said Peachtree Ridge has tried to avoid this gap by not letting students go more than one semester without taking the subject again. Peachtree Ridge students also routinely outperform the state average on exams, including the SAT.

Some tests scores at Shiloh have improved since block scheduling began, but teachers say the problems outweigh the benefits.

The loss of instruction time is a concern, said Shiloh math teacher Stephen Dartt, who chaired the Shiloh committee that decided this school year to eliminate block scheduling. Also, he said, teachers must squeeze an entire year's worth of lessons into one semester, meaning some enrichment activities may be cut.

"If our primary concern is student learning, I don't know how you can be a proponent of block schedule," Dartt said. "I wish we could get rid of it next year."

A different Shiloh group decided last year to move off the block schedule at the end of this school year. But that recommendation came before Tatum moved to the school. She wanted more information and the chance to consider the issue. She assembled a group of about 10 teachers, administrators and one parent to determine whether the block schedule would remain.

They visited schools in Alabama and South Carolina that had abandoned the program.

At first, parent Howard Whelchel was skeptical of moving away from the program school leaders once touted because his daughter, Morgan, liked it. He changed his mind after sitting on the Shiloh study committee.

"If you look at the pluses and minuses, it is an easy decision," Whelchel said. "You have to look at what is best for the majority and I believe going back to a traditional schedule is best for all the kids."

Still, Tatum wanted a year's delay to explain the decision to parents and to help prepare students. For example, without a block schedule, students may need to attend summer school to retake courses they failed because they will no longer have the time to do so during the regular school year.

Tatum said the first year of the transition may present a challenge as teachers must redo lesson plans and adapt to shorter class periods.

BLOCK SCHEDULE IN GWINNETT

A study of how block scheduling is viewed by the only two Gwinnett high schools using the system:

Shiloh

• Enrollment: About 2,200

• Background: Began block schedule in 1999 but plans to return to a traditional six-period class day in August 2008.

• Reasons for the change:

— Students spend fewer hours on most subjects with a block schedule, which divides the day into four 90-minute periods. Because each class meets for half the school year, each subject receives about 135 hours of classroom time. A traditional schedule, with six 55-minute periods each day the entire school year, gives students about 165 hours on each subject.

— Students in sequential courses, such as languages, may have to wait too long before they can take the next class in a sequence.

— The 90-minute class is too long to maintain students' attention.

Peachtree Ridge

• Enrollment: About 3,000

• Background: Began block schedule August 2003 and plans to continue.

• Reasons to keep the system:

— Students take eight courses a year instead of six, so have more time for electives and fine arts.

— Students take two electives and two academic subjects each semester so they can balance hard courses with easier ones.

— A 90-minute class gives teachers more time for hands-on projects, such as science experiments or group activities.

Sources: Local schools, Gwinnett County Public Schools.