Experts in detecting children's learning disabilities remain in two camps: One asserts IQ tests are a critical tool in diagnosing children who need special attention, while another faction asserts that the "response to intervention" (RTI) model holds more promise. Speakers discussed the merits and pitfalls of both approaches at the 11th Annual Institute for Psychology in the Schools, a pre-meeting workshop at APA's 2004 Annual Convention.

Diagnosing learning-disabled children is a complicated process, explained psychologist Randy Kamphaus, PhD, of the University of Georgia. That's because learning-disabled children often show normal or above average intelligence on IQ tests, but fail to achieve academically. To pinpoint this difference, schools have traditionally tested children and measured the discordance between their IQ and their achievement, he said. But this protocol can be problematic for schools when children with very high IQs but mid-level achievement receive learning-disability services while other lower intelligence, lower achievement children go untreated.

That tension has led to the emergence of the RTI assessment model, which, instead of measuring intelligence and achievement in numbers, identifies children who are failing to succeed, gives them remedial assistance, attends to its effect and then determines if further services are merited, Kamphaus said. But, he noted, the technique lacks empirical support and doesn't detect all the children who need services. RTI has also been shown to inappropriately identify children with mental retardation or emotional problems as learning disabled. Moreover, it fails, he said, to provide researchers a base with which to improve testing.

"While we can try to develop intelligence testing without numbers, it won't work," he said. "The intelligence test is our stethoscope, like it or not."

Kamphaus advocated for limiting the number of students a school can deem learning disabled and eligible for services. That, he believes, would force more accurate diagnosis of the causes of a child's academic failure: Schools would have an incentive to determine if learning problems were caused by other factors, like emotional issues, because those alternate diagnoses could open more spots for truly learning-disabled children.

"Caps will encourage schools to think more critically of who merits a diagnosis of learning disabled," Kamphaus said.

Alternatively, psychologist Linda Siegel, PhD, of the University of British Columbia, argued for the RTI model's superiority to IQ testing. Her research on a classroom screening model similar to RTI indicates that most elementary school children who have academic trouble in an initial screening catch up with peers when offered a small amount of classroom assistance. Those who don't improve, she finds, are then easily identified and offered a range of assessments and interventions, which subsequently rule out mental retardation and emotional problems. As such, schools don't need to resort to mass quantitative testing, she said.

"The philosophy gets away from the screening model and focuses on outcomes," Siegel explained. "We find the kids who need our help this way. I have yet to be convinced that there is some need for the IQ test [when diagnosing learning disabilities]."