Will the definition of learning disabilites change any time soon?
The definition of learning disabilites has changed significantly over the years. Many years ago the LD definition was written right out of the Illinois Test of Psycho-linguistic Abilities (ITPA) test. It was used exclusively for measuring how students processed information. Someone looked closely at the reliability coefficients, and started asking questions e.g. Is this reliable? They stopped using it because it was very unreliable – the kids tested poor one day and good the next. The Slingerland test was popular but did not meet reasonable psychometric standards for test development and was abandoned by state policy makers. The Slingerland test wasn’t normed referenced so it didn’t give information about normality at different ages, and didn’t have necessary statistical foundations that could ensure reliability. Same as the ITPA it was thought to be unreliable (In fact, many tests have this problem). That’s why we have a generic “discrepancy model”: where a student must show a signifi
