GAINESVILLE, Fla. — Students with mental retardation are far more likely to be educated alongside typical students than they were 20 years ago, a University of Florida study has found.

However, the trend once known as “mainstreaming”— widely considered the best option for such students – appears to have stalled in some parts of the country, the study’s authors report. And a student’s geographic location, rather than the severity of his disability, often determines how he will spend his school days, the researchers say.

“We’ve known for a long time that students with MR (mental retardation) are better off educationally if they can spend at least part of the day in a typical classroom,” said James McLeskey, chair of special education in UF’s College of Education and an author of the study. “We’ve found that there are still lot of students who could be included in the general classroom but aren’t included.”

Before the mid-1970s, most children with mental retardation were completely segregated from other children in the school system, if they were formally educated at all. Society widely viewed these children as uneducable, and those who did attend school were sent to institutions solely for children with mental retardation.

Both children and their parents often viewed these institutions as dehumanizing and ineffective – and by the late 1960s, educators had assembled a large body of research to show that children with mental retardation did indeed perform much better when schooled, at least part-time, among the general student population. That research led Congress to pass a 1975 law requiring a more inclusive environment for students with mental retardation.

Surveys in the 1980s and early 1990s showed that schools had made little progress toward implementing that mandate. In an article published in the spring 2006 issue of the journal Exceptional Children, UF researchers – including doctoral candidates Pam Williamson, David Hoppey and Tarcha Rentz – revisited the question, taking a comprehensive look at placement rates for students with mental retardation in all 50 states and the District of Columbia during the 1990s. They found some very good news.

“Inclusion seems to have genuinely caught on in the 1990s,” said Williamson, the lead author of the study. “By the end of the decade, a student with MR was almost twice as likely to be educated in the general classroom as a similar student the beginning of the decade.”

In 1990, almost three-fourths of students with MR were educated separately from their typical peers, learning in separate classrooms or entire schools dedicated to children with mental retardation. By 2000, only slightly more than half of students with MR were educated separately.

Still, a handful of states – Idaho, Kansas, Minnesota, New Hampshire, North Dakota, Oregon, South Dakota and Vermont – accounted for much of the gain seen nationwide, with many other states marking little or no progress.

A simple move across state lines, the researchers say, can have a major impact on a child’s educational career. Various states have widely different policies on who can be identified with mental retardation, and how they are educated. Some states identify mental retardation in as few as three out of every 1,000 students; others identify as many as 30 students per 1,000. Demographically similar states such as Alabama and Mississippi differ widely in their reported rates of mental retardation – suggesting the differences are due to policy, not environmental factors.

“For a student with mental retardation, geographic location is possibly the strongest predictor of the student’s future educational setting,” Williamson said.

Many of these students can have functional work lives in adulthood, Williamson said. However, if they aren’t exposed to their peers in the general classroom, students with MR may not pick up the social and academic skills they need to do so.

Inclusion can also have a beneficial effect for students already in the general classroom. When typical students attend school with classmates who have MR, the researchers say, they learn leadership skills and become more tolerant. They even score higher, as a group, on standardized tests.

“The inclusive classroom environment seems to work better for students who are struggling, academically, but not identified as having MR,” McLeskey said. “That tends to bring up averages on test scores for typical students in the entire class.”

In the current era of high-stakes testing, that effect could work to the benefit of students with MR. Under past school accountability rules, many states did not count the scores of students in MR-only classes when conducting statewide achievement tests – an incentive to administrators to keep students with mental retardation out of the general classroom.

Under the No Child Left Behind Act, however, schools must report test scores of all students, including those in separate special education classes.

“All these students count now, and schools have an incentive to improve their scores,” McLeskey said. “Inclusion seems to be the best way to do that.”