UBC Theses and Dissertations
The test of language competence : a validity study with language disabled and normal children Ainsworth, Cheryl Anne
This study investigated the validity and related psychometric characteristics of the Test of Language Competence (TLC), published in 1985 by Wiig and Secord. The TLC was developed as a measure of higher order language functioning in children and adolescents between the ages of nine and eighteen years. Evidence concerning the psychometric characteristics of the TLC is reported in the test manual; however, to date, no studies addressed primarily to the subject of TLC validity have been reported in the literature. Moreover, no information is available concerning the effectiveness of its use with local school children. This study endeavored to examine the technical characteristics of the TLC using data obtained from 23 language disordered (LLD) and 23 control subjects sampled from the local school population. At the same time, the criterion-related validity of an informal language sample analysis was investigated. Item analysis statistics, including indices of item difficulty, item discrimination, internal consistency, and interrater reliability were prepared for the TLC. Discriminant function analyses were used to assess criterion validity of the TLC, with and without corrections in TLC scores for Verbal IQ. Because of the multiethnic nature of the sample, English as a second language (ESL) and English as a first language (EFL) group means were tested for significant differences on six variables. LLD and control group performance on the language sample analysis were tested for significant differences, using Wilcoxon rank sum tests. Results of the item analyses indicated support for the internal consistency of the TLC subtests and the test composite, with the exception of Subtest Two (Making Inferences), which obtained an internal consistency coefficient below the designated .8 criterion. Subtest Two and Subtest Three (Recreating Sentences) were found to contain items of questionable validity, and all four subtests contained items that were misordered in terms of difficulty. Subtests Two and Three exhibited satisfactory criterion validity; however, Subtest One (Understanding Ambiguous Sentences) and Four (Understanding Metaphoric Expressions) failed to discriminate between LLD and Control groups in a stepwise analysis. The language sample analysis discriminated between the two groups. Possible explanations for the findings, along with implications for clinical practice and recommendations for further research, are discussed.
Item Citations and Data