Defining math disability : the impact of using different cut offs when assessing the cognitive characteristics of math disabled participants

• Main Author: Pinkerton, Neil A.
• Language: English
• Published: University of British Columbia 2011
• Online Access: http://hdl.handle.net/2429/39840

Mathematics disabilities (MD) can cause serious difficulties for children throughout their education. However, there is a lack of consensus in the literature regarding how MD should be defined. This makes it difficult to compare results across studies and to determine the overall cognitive profile of MD. The present study investigated the cognitive profiles of participants with MD defined using various cut off criteria and using different assessment measures. Further, this study endeavoured to investigate the differences between those who have MD at one time point and those who have MD at two time points (MD persistent). Over 700 participants were recruited from the North Vancouver school district to participate in this study. Participants were evaluated over two years (grades 2 and 3). Performance was measured using 16 different cognitive measures and 4 achievement tests. Scores on the achievement tests were used to assign MD status. A series of t-tests were conducted to determine whether there are differences between the cognitive profiles of those defined as MD using a 10th percentile cut off (MD10), a 25th percentile cut off (MD25), and a low achieving score between the 11th and 25th percentiles MD(11-25) when compared to typically achieving students (TA). Cut offs were based on performance on two separate math achievement tests: the Woodcock-Johnson Third Edition (WJ III) Calculation test and the Woodcock-Johnson Third Edition Applied Problems test. This study concludes that MD10, MD25, and MD(11-25) all represent similar enough cognitive profiles when compared to the TA group that using a 25% cut off to define MD will suffice for future research. Furthermore, the results suggest that the MD persistent group has a similar enough profile to the terminus point group that additional caution should be used when studying MD persistent in the future. The cognitive profiles of the MD groups are described and implications for research and practice are discussed.