J Am Acad Audiol 2001; 12(01): 7-14
DOI: 10.1055/s-0041-1741115
Original Article

Relation Between Slopes of Word Recognition Psychometric Functions and Homogeneity of the Stimulus Materials

Richard H. Wilson
Auditory Research Laboratory, James H. Quillen VA Medical Center, Mountain Home, Tennessee and Departments of Surgery and Communicative Disorders, East Tennessee State University, Johnson City, Tennessee
Anne Strouse Carter
Auditory Research Laboratory, James H. Quillen VA Medical Center, Mountain Home, Tennessee and Departments of Surgery and Communicative Disorders, East Tennessee State University, Johnson City, Tennessee
› Author Affiliations


This tutorial paper examines the relation between the slope of a mean word recognition function and the homogeneity or variability (with respect to recognition) of the individual stimulus items that compose the test materials. This was studied in terms of both the location (Cartesian) and slope of the psychometric functions of the individual words that compose the materials. Word recognition performances were measured for 100 CID W-22 (Hirsh) words and 100 PB-50 (Rush Hughes) words in quiet (0 to 56 dB HL in 8-dB steps) on 12 subjects with normal hearing. The functions for the individual W-22 words were more homogeneous (less variable) than were the functions for the individual PB-50 words. The mean function for the W-22 words was steeper (3.1%/dB) than the function for the PB-50 words (1.9%/dB). This evaluation of the individual words demonstrates the direct relation between variability of the test items and the slope of the mean psychometric function. The more homogeneous performance is on the individual test items with respect to both location and slope, the steeper the slope of the mean psychometric function.

Abbreviations: ANOVA = analysis of variance, CD = compact disc

Publication History

Article published online:
28 February 2022

© 2001. American Academy of Audiology. This article is published by Thieme.

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