Accounting for individual differences when comparing the effectiveness of remedial language teaching methods

Two language intervention methods were compared on their effectiveness at improving syntactic structures as measured by gain scores on the Developmental Sentence Scoring (DSS) procedure. Forty-one expressive language delayed children were assigned to either an Interactive approach ( n = 25) or a Programmed approach ( n = 16), following a series of 13 pre-training diagnostic tests. An analysis of group mean DSS gain scores did not indicate a significant difference between the two teaching methods. However, when individual differences on the pre-training tests were incorporated into further group comparisons, disordinal Aptitude × Treatment interactions occurred for measures of intelligence, initial syntax level, and visual-motor integration. The Interactive approach optimized syntax improvement for children with relatively high pre-training scores on each of the three measures, whereas the Programmed approach resulted in superior syntax performance for low-scoring children.