The syntactic density score revisited: which of its components matter in the oral language of 9-15 year olds?

Abstract

The Syntactic Density Score (SDS) is an index of language complexity computed from 10 variously weighted component variables. The SDS has been criticized as being redundant with one of its own component variables, as being arbitrarily weighted, and as having a serious scoring anomaly. The purposes of this study were to determine if group effects would be found by using the raw scores of the 10 variables without the weightings and to see which of these variables would contribute most to group differences among older children. Language samples from 72 learning disabled students and a matched group of normally achieving peers (age range 9.0 to 15.0) were analysed. A MANOVA revealed no significant overall effect for ability nor for ability X age inter action. These was, however, a significant effect of age. Discriminant analysis with stepwise variable selection identified gerunds, verbs, prepositional phrases and number of subordinate clauses per T-unit as components of the SDS which could be used to determine age group differences. Similar analysis of com ponent variables of the SDS is recommended for future studies, rather than using the derived SDS itself.