While many schools use an IQ-Achievement Discrepancy model to identify the presence of a learning disability, that is students with learning disabilities show an unexpected gap between their potential and achievement, there is a push for schools to use a Response to Intervention (RTI) method to identify learning disabilities (LD). In RTI, students who do not respond to intensive intervention would be identified as disabled. Advantages and disadvantages exist for both methods.

IQ-Achievement Discrepancy

Though there is a movement against the discrepancy model, some educators say it has a valid basis — it documents the unexpected underachiever. Other educators say that though the model is flawed, we should use it but with greater integrity.

However, arguments against the discrepancy method abound. One argument is that the high number of students identified as LD through this method is suspect. Also, results aren’t consistent: one state, and even districts, may have a high number of students with LD while another has few. Some research has even shown that the same team using the discrepancy model will not identify the same students as having LD.

One of the most pressing arguments against the discrepancy model is its "wait and fail" aspect. Students must be in third or fourth grade to have a discrepancy large enough to be identified as disabled.

The discrepancy model is further criticized because IQ tests can be biased against certain racial groups or those who are indigent.

Response to Intervention

At first glance, RTI seems to address the wait to fail concern. With RTI, low achievers are identified as quickly as possible and provided intensive and validated instruction.

However, RTI also raises concerns. First, because we do not have effective measures for children in preschool, RTI can present its own version of wait to fail. Second, there is no guarantee that a student who responds to interventions will continue to progress when he or she returns to the general education classroom.

Other questions exist as to how RTI will be implemented. For example, how long should a child receive interventions and how extensive must non-responsiveness be before a student is identified as disabled? Another concern is that few intervention strategies exist for academic areas other than reading or for students at the middle or high school levels.

Even selecting intervention strategies could be problematic. Problem solving interventions allow special education teachers to individualize by selecting the interventions to use but may compromise the program’s integrity. With standard protocol interventions, which involve a teaching package, teachers lose the ability to individualize.

In addition, teachers will need to teach, test, and keep data in ways they are neither accustomed nor trained to do.

Finally, educators say RTI is untested and we don’t know how to scale it to a national level. Thus far, RTI for reading has been implemented in only a handful of states.

CEC's Position

For the reauthorization of IDEA, CEC said more research needs to be done before moving to RTI to identify LD. Our comments included the following:

  • The use of research-based interventions in early reading offers a real opportunity for more at-risk students, including many with LD, to acquire needed beginning literacy skills. However, the use of scientific research-based intervention cannot determine whether a child is or is not learning disabled. Instead, students who do not display meaningful gains and who appear to be unresponsive to intervention are candidates for referral for special education evaluation.
  • Insufficient data are available regarding the long-term effects of RTI on student outcomes.
  • The ability-achievement discrepancy formula should not be used as the sole criterion to determine eligibility. However, discrepancy remains a hallmark of specific learning disabilities.
  • CEC supports using methods other than the discrepancy formula. However, there are no research-based alternatives that have been sufficiently validated at this time.
  • Non-responsiveness to intervention should trigger a multi-disciplinary evaluation and should not, in itself, be considered an indication of a specific learning disability.

Adapted from "Changing the Way We Identify Learning Disabilities," CEC Today, Jan-Feb-March 2004.