Reducing class size has traditionally been seen as an important way to improve a student's educational experience.

Many public opinion studies have shown that both teachers and parents favor small class size. Teachers who go on strike are often seeking lower classroom numbers among other better working conditions. Many often believe that smaller classes would permit teachers to give more personal attention to their student. This can theoretically lead to improved academic results for student.

But one recent study suggests there is not much research-based evidence to support this idea. The researchers say the idea of smaller class sizes has been studied and debated for many years. However, they noted a lack of clear research to support class size reductions.

The study notes that one of the main problems with reducing class sizes is that it can have very high costs. Increasing class size is one of the most common ways school systems control education spending. Financial limitations make it very difficult for many schools to reduce the number of students in the classroom.

The teachers' goal was to examine the major research studies already completed on the subject. They especially centered on studies that tried to measure whether the smaller class size resulted in greater success for students.

'The researchers conclude that there is some evidence to suggest that reducing class size may lead to some improvement in a student's rending achievement. But they said "the effect is very small." They found just a 53-percent chance that a randomly selected test score from a student from a small class would be higher than the selected score of a student from a lager class. For mathematics achievement, the result was 49 percent. This led the researchers to conclude that there would be little benefit to math students in a smaller class size.

Amy Maplethorpe, a first-year speech-language teacher at Raymond Ellis Primary School, used tennis balls, a hot glue gun, Mod Podge and a bit of paint to create two chairs that help students with sensory (感官的) problems.

According to the school’s Facebook page, which became very popular, the chairs provide a “different texture (质地) to improve sensory regulation (调控).”

Maplethorpe told ABC News that the chairs will service about 15 to 20 students. Children with sensory problems often have a hard time “dealing with sensory information”. Things, such as coats, blankets and Maplethorpe’s chairs, often comfort a student.

Maplethorpe was excited to create the chair after seeing something similar on a website, and she made some changes to the idea.

“I wanted to continue to help students with sensory problems at Ellis and provide a different kind of seat for the students,” she continued. “I was excited that this chair could help my students.’’

The two chairs are now in the school’s sensory room, which was created recently, according to headmaster, Beth Kiewicz.

“When a child’s sensory needs are met, we then can move on to their needs in study,” Kiewicz, who has led the school for six years, told ABC News.

Maplethorpe said the chairs have already made a difference for some of her students.

“Students have become more patient, and have followed directions, while waiting for activities,” she said.

Students in Washington, D.C., will return to classrooms this month to begin a new school year. But at least five percent of their teachers will not return with them. Last month, the District of Columbia public schools told two hundred six teachers that they are not good enough to stay.

The school system dismissed seventy-five teachers last year. It was the first year of a new teacher rating system. Experts say such large numbers of dismissals are rare in American schools. But in Washington the rating system is not governed by the labor contract (劳务合同) with teachers union. So school officials have more freedom. The system is called IMPACT. Teachers are observed in the classrooms five times a year for at least thirty minutes each time. They are also judged by student test scores.

Emily Cohen, a policy director, says the National Council supports the IMPACT system She says, “This is an evaluation method that is finally able to find who is highly effective and who is ineffective.” Michelle Rhee created the IMPACT system. She gained national attention for her aggressive reform efforts when she led the troubled school system in the nation’s capital.

Some Washington teachers say their rating depend too heavily on test scores. For some teachers, half of their rating is based on how well their students do. But Emily Cohen says test scores are important. “Testing is probably one of the-it’s the most objective data that we have on teacher performance. So it’s not just looking at student test performance, it is using other sources of data.”

Almost sixty percent of the teachers who were rated “minimally effective” last year stayed in the school system and improved. School officials say these teachers received help to become better.