Construct validity of modified time-interval analysis in measuring stuttering and trained speaking patterns

PurposeThe aim of the present study was to examine the construct validity of modified time-interval analysis. This measure allows judgments on stuttered and fluent speech as well as trained speaking patterns and might be valuable for outcome studies.MethodConstruct validity was investigated in an intervention study with two treatment groups (24 clients received stuttering modification treatment, 30 clients received fluency modification treatment) and a control group (38 stuttering adults). All participants were interviewed during surprise phone calls before and after treatment; the speech samples were analyzed by means of modified time-interval analysis and stuttering frequency counts.ResultsThe outcomes confirmed prior hypotheses for the most part. First, the amount of trained speaking patterns after therapy was significantly higher in both treatment groups than in the control group. Secondly, longitudinal changes in the treatment groups met prior expectations based on differing treatment goals and exceeded the changes in the control group. Modified time-interval analysis was sufficiently sensitive to detect changes of speech fluency, but underestimated spontaneous fluent speech when trained speaking patterns were applied.ConclusionThe present study supports construct validity of modified time-interval analysis in measuring stuttering and trained speaking patterns, but also reveals a lack of accuracy.Educational objectives: At the end of this activity the reader will be able to (a) explain different forms of validity in relation to the use of modified time-interval analysis, (b) evaluate whether construct validity of modified time-interval analysis has been supported by the outcomes of an intervention study and (c) describe the usefulness and limitations of modified time-interval analysis for future research.

► Modified time-interval analysis measures speech fluency after stuttering treatment.
► We investigated construct validity of this measure in an intervention study.
► Changes in speech fluency were captured by modified time-interval analysis.
► Modified time-interval analysis is less accurate than traditional frequency counts.