A common method of determining eligibility criteria for specific learning disability is to identify discrepancies in intellectual processes and academic achievement. While the “discrepancy model” has fallen out of favor, many school districts have turned to a similar model of Patterns of Strengths and Weaknesses (PSW). This model looks at overall IQ or a relative strength in intellectual functioning and compares it to a relative weakness in intellectual functioning and a relative weakness in academic achievement. A significant “discrepancy” between strengths and weaknesses, along with a strong correlation between weaknesses, gives one piece of needed evidence. Other pieces of evidence to determine eligibility under the PSW model include observation data (including a discrepancy analysis with another student), grades (traditional letter grades and/or standards-based grading), and response to school-wide intervention programs (e.g., PBIS, MTSS). There are benefits and drawbacks to this model, just as there is to RTI. Let’s review the positives first.
Standard Administration and Scoring
The PSW model uses standardized tests to assess IQ and academic achievement. Contrary to what some may think, there is not one blanket test that is given to all students. Rather, school psychologists choose the cognitive and academic test to use based on a number of factors, such as language ability, age, cultural factors, and referral question(s). While standardization samples are not perfect (more on that later), the standard administration is what is a strength. There is virtually no guess work on how to administer testing items and how to score those items. Many of these tests allow for computer scoring to reduce human error. Some of them even have iPad administration to help with administration and scoring rules. This standardization allows for more reliable results and higher confidence when interpreting results.
As mentioned previously, cognitive (IQ) and academic tests are not the only evidence used in eligibility decisions. PSW uses a holistic approach of putting cognitive and academic test scores in the context of other factors in order to come to a conclusion. Test information is combined with observation data, grades, standards-based progress monitoring, and other data collected by parents, teachers, administrators, and related service providers. Most professionals will agree that more data equals to better decision making and planning. The PSW model not only offers a holistic view, but is also streamlined with cognitive and academic tests instead of weeks instead of additional weeks of interventions (and in many cases, the tests give better direction on selection of interventions).
Meets IDEA and State Rules/Regulations
“Specific learning disability means a disorder in one or more of the basic psychological processes involved in understanding or in using language, spoken or written, that may manifest itself in the imperfect ability to listen, think, speak, read, write, spell, or to do mathematical calculations, including conditions such as perceptual disabilities, brain injury, minimal brain dysfunction, dyslexia, and developmental aphasia.
Disorders not included. Specific learning disability does not include learning problems that are primarily the result of visual, hearing, or motor disabilities, of intellectual disability, of emotional disturbance, or of environmental, cultural, or economic disadvantage” (IDEA 2010).
PSW specifically targets psychological processes where other methods do not. This is accomplished through the use of various cognitive tests that assess broad and narrow band psychological processes. While all tests are not created equal, school psychologists have the flexibility to choose tests that best align with the target student. The use of specific tests with psychometric properties to assess for psychological processes allows for IDEAs condition to be met with a higher degree of reliability.
PSW is not perfect; I will address the drawbacks in the next post. However, there are benefits that make it a similar and more reliable process than RTI in many ways, while offering a more complete picture than a standard discrepancy model.