Elements of phonological interventions for children with speech sound disorders: The development of a taxonomy

Our aim was to develop a taxonomy of elements comprising phonological interventions for children with speech sound disorders. Method: We conducted a content analysis of 15 empirically supported phonological interventions to identify and describe intervention elements. Measures of element concentration, flexibility, and distinctiveness were used to compare and contrast interventions. Results: Seventy-two intervention elements were identified using a content analysis of intervention descriptions then arranged to form the Phonological Intervention Taxonomy: a hierarchical framework comprising 4 domains, 15 categories, and 9 subcategories. Across interventions, mean element concentration (number of required or optional elements) was 45, with a range of 27 to 59 elements. Mean flexibility of interventions (percentage of elements considered optional out of all elements included in the intervention) was 44%, with a range of 29% to 62%. Distinctiveness of interventions (percentage of an intervention’s rare elements and omitted common elements out of all elements included in the intervention [both optional and required]) ranged from 0% to 30%. Conclusions: An understanding of the elements that comprise interventions and a taxonomy that describes their structural relationships can provide insight into similarities and differences between interventions, help in the identification of elements that drive treatment effects, and facilitate faithful implementation or intervention modification. Research is needed to distil active elements and identify strategies that best facilitate replication and implementation.