Reliability and Concurrent Validity of the Likert-Type Stuttering Severity Scale and the Visual Analog Scale in Turkish-Speaking Adults Who Stutter

Mutlu A. İ., Uçal İ.

INTERNATIONAL JOURNAL OF LANGUAGE & COMMUNICATION DISORDERS, vol.61, no.5, pp.70325, 2026 (SCI-Expanded, SSCI, Scopus)

  • Publication Type: Article / Article
  • Volume: 61 Issue: 5
  • Publication Date: 2026
  • Journal Name: INTERNATIONAL JOURNAL OF LANGUAGE & COMMUNICATION DISORDERS
  • Journal Indexes: EBSCO Communication Source, Academic Search Ultimate (EBSCO), Biomedical Reference Collection: Corporate Edition (EBSCO), Business Source Ultimate (EBSCO), Communication Source (EBSCO), Education Source Ultimate (EBSCO), Health Research Premium Collection (ProQuest), Humanities Source Ultimate (EBSCO), Scopus, Science Citation Index Expanded (SCI-EXPANDED), Social Sciences Citation Index (SSCI), CINAHL, Education Abstracts, Educational research abstracts (ERA), EMBASE, ERIC (Education Resources Information Center), EBSCO Education Source, MEDLINE, MLA - Modern Language Association Database, Psycinfo, MLA International Bibliography
  • Page Numbers: pp.70325
  • Ankara Yıldırım Beyazıt University Affiliated: Yes

Abstract

ABSTRACT

Purpose

This study examined the test–retest and inter-rater reliability of non-clinician severity judgments using two brief rating tools—the 11-point Severity Scale (SEV) and the Visual Analog Scale (VAS)—and evaluated their concurrent validity with clinician-rated Stuttering Severity Instrument-4-Turkish version (SSI-4-TR) scores.

Method

This observational cross-sectional study used speech samples from 15 adults who stutter as stimulus materials. Recordings were evaluated by two speech-language therapists (SLTs) and two independent groups of non-clinician raters (n = 26 per group). SLTs assessed stuttering severity using the SSI-4-TR. One non-clinician group rated severity using a VAS, whereas the other used SEV. All ratings were completed online across three sessions. To examine temporal stability, 30% of the samples were re-rated after a one-week interval.

Results

Both tools demonstrated excellent test–retest reliability, with intraclass correlation coefficients of 0.997 for the VAS and 0.987 for the SEV. Inter-rater reliability was moderate, with ICC values of 0.656 for the VAS and 0.573 for the SEV. Both scales showed strong positive correlations with SSI-4-TR scores, with correlation coefficients of 0.835 for the VAS and .814 for the SEV (p < 0.001).

Conclusions

The findings indicate that the VAS and SEV demonstrated high test–retest reliability and moderate inter-rater reliability and showed strong associations with SSI-4-TR scores, supporting the use of brief perceptual rating scales as practical screening instruments in large-scale and time-limited clinical and research settings where rapid and resource-efficient assessment is required.