Intervention dosage is an active ingredient that requires investigation for precision interventions to be developed. Dose in interventions treating communication disorders is measured in within and across interventions sessions, with some early research showing within session dose factors are more influential to outcomes. This study explores the impact of four dose elements on the inferential and referential language gains from three assessment times (pre, post and follow-up) made by children with communication disorders receiving the Launch to School (L2S) intervention. A clinical caseload of 107 preschoolers: 87 with Language Disorders (LD) and 34 non-LD (mostly speech sound disorder) participated in L2S – an intervention designed for multicultural children with emergent literacy vulnerabilities. A multilevel model was used (age and multilingual status controlled). Diagnosis (LD and non-LD) and four dose variables were placed in the model, two within intervention settings: number of teaching moments (dose), the length of time of the session (dose frequency); and two across sessions: administration daily or weekly (dose distribution), and children’s attendance to sessions (dose intervention length). Referential and inferential language was assessed on the Quick Test of Language. A lower dose within the session (mean 8 teaching moments /minute) resulted in better outcomes immediately post intervention for LD children but not non-LD children. Children who attended less sessions (dose intervention length) but received the higher dose of teaching moments within the sessions they attended made significantly greater gains in follow-up. The group who received longer dose within the session (dose frequency) had significantly lower outcomes at pre and post but not at follow-up. Within session dose factors were more influential to referential and inferential language outcomes, and those influences differed by diagnosis. These findings have implications for how intervention is conducted within the sessions.

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