Intelligibility in Context Scale: Normative and Validation Data for English-Speaking Preschoolers Purpose The purpose of this study was to describe normative and validation data on the Intelligibility in Context Scale (ICS; McLeod, Harrison, & McCormack, 2012c) for English-speaking children. Method The ICS is a 7-item, parent-report measure of children's speech intelligibility with a range of communicative partners. Data were ... Research Article
Research Article  |   July 01, 2015
Intelligibility in Context Scale: Normative and Validation Data for English-Speaking Preschoolers
 
Author Affiliations & Notes
  • Sharynne McLeod
    Charles Sturt University, Bathurst, New South Wales, Australia
  • Kathryn Crowe
    Charles Sturt University, Bathurst, New South Wales, Australia
  • Ameneh Shahaeian
    Charles Sturt University, Bathurst, New South Wales, Australia
  • Disclosure: The authors have declared that no competing interests existed at the time of publication.
    Disclosure: The authors have declared that no competing interests existed at the time of publication.×
  • Correspondence to Sharynne McLeod: smcleod@csu.edu.au
  • Editor: Marilyn Nippold
    Editor: Marilyn Nippold×
  • Associate Editor: Victoria Joffe
    Associate Editor: Victoria Joffe×
Article Information
Speech, Voice & Prosodic Disorders / Cultural & Linguistic Diversity / Research Issues, Methods & Evidence-Based Practice / Research Articles
Research Article   |   July 01, 2015
Intelligibility in Context Scale: Normative and Validation Data for English-Speaking Preschoolers
Language, Speech, and Hearing Services in Schools, July 2015, Vol. 46, 266-276. doi:10.1044/2015_LSHSS-14-0120
History: Received December 21, 2014 , Revised March 26, 2015 , Accepted April 23, 2015
 
Language, Speech, and Hearing Services in Schools, July 2015, Vol. 46, 266-276. doi:10.1044/2015_LSHSS-14-0120
History: Received December 21, 2014; Revised March 26, 2015; Accepted April 23, 2015

Purpose The purpose of this study was to describe normative and validation data on the Intelligibility in Context Scale (ICS; McLeod, Harrison, & McCormack, 2012c) for English-speaking children.

Method The ICS is a 7-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 ranging in age from 4;0 (years;months) to 5;5 (37.0% were multilingual).

Results The mean ICS score was 4.4 (SD = 0.7) out of a possible total score of 5. Children's speech was reported to be most intelligible to their parents, followed by their immediate family, friends, and teachers; children's speech was least intelligible to strangers. The ICS had high internal consistency (α = .94). Significant differences in scores were identified on the basis of sex and age but not on the basis of socioeconomic status 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). A sensitivity of .82 and a specificity of .58 were established as the optimal cutoff. Test–retest reliability and criterion validity were established for 184 children with a speech sound disorder. There was a significant low correlation between the ICS mean score and percentage of phonemes correct (r = .30), percentage of consonants correct (r = .24), and percentage of vowels correct (r = .30) on the Diagnostic Evaluation of Articulation and Phonology (Dodd, Hua, Crosbie, Holm, & Ozanne, 2002). Thirty-one parents completed the ICS related to English and another language spoken by their child with a speech sound disorder. The significant correlations between the scores suggest that the ICS may be robust between languages.

Conclusions This article 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 because mean ICS scores were not affected by socioeconomic status, number of languages spoken, or whether the ICS was completed in relation to English or another language. The ICS is recommended as a screening measure of children's speech intelligibility.

Acknowledgments
This research was supported by the following sources: Australian Research Council Discovery Grant DP130102545 (awarded to Sharynne McLeod, Elise Baker, Jane McCormack, Yvonne Wren, and Sue Roulstone); Australian Research Council Future Fellowship FT0990588 (awarded to Sharynne McLeod); and the Charles Sturt University Research Institute for Professional Practice, Learning and Education. We acknowledge the insights and support from Linda Harrison, Jane McCormack, Sarah Masso, Elise Baker, Yvonne Wren, Sue Roulstone, Sarah Verdon, and Helen Blake. We also thank Felicity McKellar and Charlotte Howland for data entry.
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