Extended Practice of Basic Addition Facts: Strategy Changes in Learning-Disabled Students

Basic addition facts performance of learning-disabled (LD) children was assessed prior to and following a period of extended practice in fact production. Consistent with current theoretical discussions (e.g., Siegler, 1987), effects of the extended practice were assessed through an examination of changes in (a) problem latencies, (b) mixed strategy usage, and (c) slope parameters of the regression function relating individual problem latencies to the size of the minimum addend. For the sample as a whole, there were reductions in response latency and in the slope of the regression function following practice. However, there were actually four discriminable groups in the sample, each slower in fact production than same-age normally achieving children but differing in their strategy usage patterns. Accordingly, differential effects of practice were expected for each group; the patterns of changes in latency, mixed strategy usage, and slope parameters were consistent with these predictions. Comparisons are made to extant data on normally achieving children. The data generally support the conclusion that the performance of most of these LD children is developmentally delayed (rather than developmentally different) relative to that of normally achieving children. The results are discussed from the perspective of optimizing instructional time through sensitive assessment of entry level skills and prediction of likely changed benefits, given these skill levels and other incoming student characteristics. The implications for strategy identification of both differences within individuals and differences between individuals are considered, as are theoretical and methodological issues.