Generalizability Theory II Application to Perceptual Scaling of Speech Naturalness in Adults Who Stutter Research Article
Research Article  |   June 01, 2003
Generalizability Theory II
 
Author Affiliations & Notes
  • Sue O'Brian
    The University of Sydney Australia
  • Ann Packman
    The University of Sydney Australia
  • Mark Onslow
    The University of Sydney Australia
  • Nigel O'Brian
    The University of Sydney Australia
  • Contact author: Sue O'Brian, Australian Stuttering Research Centre, Gate 2, Building D, Cumberland Campus, University of Sydney, East St., Lidcombe NSW 2141, Australia. E-mail: s.obrian@fhs.usyd.edu.au
Article Information
Speech, Voice & Prosodic Disorders / Fluency Disorders / Speech / Research Articles
Research Article   |   June 01, 2003
Generalizability Theory II
Journal of Speech, Language, and Hearing Research, June 2003, Vol. 46, 718-723. doi:10.1044/1092-4388(2003/057)
History: Received August 19, 2002 , Accepted December 11, 2002
 
Journal of Speech, Language, and Hearing Research, June 2003, Vol. 46, 718-723. doi:10.1044/1092-4388(2003/057)
History: Received August 19, 2002; Accepted December 11, 2002
Web of Science® Times Cited: 10

Generalizability theory has been recommended as the most comprehensive method for assessing the reliability of observational data. It provides a framework for calculating the various sources of measurement error and allows further design of measurements for a particular purpose. This paper gives a practical illustration of how this method may be used in the analysis of observational data. We use the ratings of 15 unsophisticated raters using the 9-point speech naturalness scale of R. R. Martin, S. K. Haroldson, and K. A. Triden (1984) to evaluate the speech of adults before and after treatment for stuttering. We calculate various sources of measurement error and use these to estimate the minimum number of raters and ratings per rater for a reliable result. For posttreatment data, the average of three independent raters, and for pretreatment data, the average of five independent raters should give a result within one scale point of the hypothetical true score for the speaker in at least 80% of samples. The example illustrates the advantages of using this method of analysis.

Acknowledgment
The authors would like to thank the raters and clients who voluntarily participated in this project.
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