Background: Data have accumulated to show that the Lidcombe Program of early stuttering intervention is a safe treatment with positive outcomes for preschoolers who stutter, and a randomized controlled trial is under way at the time of writing. Program components have not been investigated experimentally so the functionality of each component is unknown. Aims: The aim of this preliminary study was to establish the viability of a programme of research that would assess the clinical value of two program components. These components were parental verbal contingencies for stuttering and severity ratings. Methods & Procedures: In the present preliminary experiment, 38 preschool children were randomized to an experiment involving a 4-week 'dose' of treatment followed by 4 weeks without treatment. The dependent variable was the percentage of syllables stuttered (%SS) obtained from the mean %SS score from recordings on three recording occasions. Outcomes & Results: Some preliminary indications were found that parental verbal contingencies for stuttering contributed to treatment outcomes. No preliminary evidence was found for the contribution of parent severity ratings to treatment outcomes. Conclusions: It was concluded that a robust, statistical demonstration of these result would be desirable, but effect size estimates from the present data show that access to more than 650 families of stuttering preschool children would be required for such a study. Such a project would be beyond the resources of any one research group to complete in a timely manner, and a method to address this problem is proposed.