McLeod, S. & Crowe, K. & Shahaeian, A. (2015, in press April). Intelligibility in Context Scale: Normative and validation data for English-speaking preschoolers. Language, Speech, and Hearing Services in Schools.
Updated publication details:
McLeod, S. & Crowe, K. & Shahaeian, A. (2015). Intelligibility inContext Scale: Normative and validation data for English-speaking preschoolers. Language, Speech, and Hearing Services in Schools, 46(3), 266-276. doi: 10.1044/2015_LSHSS-14-0120
Purpose: To describe normative and validation data on the Intelligibility in Context Scale (ICS, McLeod, Harrison, & McCormack, 2012a) for English-speaking children.Method: The ICS is a seven item parent report measure of children’s speech intelligibility with a range of communicative partners. Data were collected from the parents of 803 Australian English-speaking children aged 4;0 to 5;5 (37.0% were multilingual).Results: The mean ICS score was 4.4 (SD = 0.7) of a possible total score of 5. Children’s speech was reported to be most intelligible to their parent, followed by their immediate family, friends, and teachers, and least intelligible to strangers. The ICS had high internal consistency (α = .94). Significant differences in scores were identified based on sex and age, but not socioeconomic status (SES) or the number of languages spoken. There were significant differences in scores between children whose parents had concerns about their child’s speech (M = 3.9) and those who did not (M = 4.6). Sensitivity of .82 and specificity of .58 was established as the optimal cut-off. Test-retest reliability and criterion validity was established for 184 children with speech sound disorder. There was a significant low correlation between the ICS mean score and percentage of phonemes correct (PPC, r =.30), percentage of consonants correct (PCC, r =.24), and percentage of vowels correct (PVC, r =.30) on the Diagnostic Evaluation of Articulation and Phonology (Dodd et al., 2002). Thirty-one parents completed the ICS about English and another language spoken by their child with speech sound disorder. The significant correlations between the scores suggest that the ICS may be robust between languages.Conclusion: This paper provides normative ICS data for English-speaking children and additional validation of the psychometric properties of the ICS. The robustness of the ICS was suggested since mean ICS scores were not affected by SES, number of languages spoken, or whether the ICS was completed about English or another language. The ICS is recommended as a screening measure of children’s speech intelligibility.