Clausal density (Guo et al., 2020)

Purpose: This study provided reference data and examined psychometric properties for clausal density (CD; i.e., number of clauses per utterance) in children between ages 4 and 9 years from the database of the Edmonton Narrative Norms Instrument (ENNI).

Method: Participants in the ENNI database included 300 children with typical language (TL) and 77 children with language impairment (LI) between the ages of 4;0 (years;months) and 9;11. Narrative samples were collected using a story generation task, in which children were asked to tell stories based on six picture sequences. CD was computed from the narrative samples. The split-half reliability, concurrent criterion validity, and diagnostic accuracy were evaluated for CD by age.

Results: CD scores increased significantly between ages 4 and 9 years in children with TL and those with LI. Children with TL produced higher CD scores than those with LI at each age level. In addition, the correlation coefficients for the split-half reliability and concurrent criterion validity of CD scores were all significant at each age level, with the magnitude ranging from small to large. The diagnostic accuracy of CD scores, as revealed by sensitivity, specificity, and likelihood ratios, was poor.

Conclusions: The finding on diagnostic accuracy did not support the use of CD for identifying children with LI between ages 4 and 9 years. However, given the attested reliability and validity for CD, reference data of CD from the ENNI database can be used for evaluating children’s difficulties with complex syntax and monitoring their change over time.

Supplemental Material S1. Coding and computation for clausal density.

Supplemental Material S2. Excel sheet for computing clausal density score.

Supplemental Material S3. Frequency (rate) of usage for each type of dependent clause by language status and age.

Supplemental Material S4. Frequency (rate) of errors collapsing across clause types.

Supplemental Material S5. Z-score calculation table for clausal density scores.

Guo, L.-Y., Schneider, P., & Harrison, W. (2020). Clausal density between ages 4 and 9 years for the Edmonton Narrative Norms Instrument: Reference data and psychometric properties. Language, Speech, and Hearing Services in Schools. Advance online publication. https://doi.org/10.1044/2020_LSHSS-20-00043