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Empirical Investigation of the Oral Fluency Compass

Background and aims

Hitherto there has been no empirically supported data on early detection of the fluency disorder known as stuttering or stammering that reflects criteria-based counselling and therapy needs. The “Redeflusskompass (Oral Fluency Compass) 2.0” is a screening tool designed to assist in decision-making when identifying an incipient stammer.


The original research project was designed to identify quality criteria for the Oral Fluency Compass and determine potential problems in its use. It was evaluated for this purpose.


Various methodical approaches were selected to enable triangulation of quantitative and qualitative data in order to assess the tool’s quality from the angle of its practical relevance and to enable a discussion – regardless of the tool’s use – about decision-making processes in the identification of an incipient stammer. A retest procedure was adopted to determine the interrater reliability of the tool in N = 79 cases. Sensitivity, specificity and criterion validity were determined in N = 60 cases by documenting the actual diagnosis and counselling. Videos of non-fluent children were played to potential users to permit further differentiation of quality criteria. Pitfalls in the use of the tool were identified by means of interviews with users and evaluated with the aid of content analysis. 


Although criterion validity (0.42, Cramer’s V) is satisfactory and sensitivity (96%) is very good, interrater reliability (0.36, Cohen’s kappa) and specificity (46%) were not convincing. Users described different problems related to their experience: for non-experts, the criteria seem to be too difficult, whereas fluency disorder specialists demand for differentiation of the listed decision-making criteria. Consequently, a toolset for identifying an incipient stammer needs to be attuned to the skills of the user. The Oral Fluency Compass has therefore been completely redesigned and there is now a Version 3.0. This is a tool that non-experts (significant caregivers, teachers etc.) can use for the early detection of a stammer. Complementary to this, the “Stotterkompass” (Stammer Compass) is a second tool tailored to the needs of specialists. It is also designed for early detection and can be used in diagnostics and therapy as an aid in initial counselling.



Project Management

Prof. Dr.  Kohler



Forschung und Entwicklung
Tel: +41 44 317 11 81

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