Does intensity matter? Preschoolers’ print knowledge development within a classroom-based intervention

The present study examined the extent to which two dimensions of intervention intensity, (dose frequency and dose) of a 30-week print-referencing intervention related to the print knowledge development of 367 randomly selected children from 55 preschool classrooms. Dose frequency refers to the number of intervention sessions implemented per week; teachers were randomly assigned to either the high-dose frequency condition (four intervention sessions per week) or the low-dose frequency condition (two intervention sessions per week). Dose refers to number of print-referencing teaching strategies used per intervention session and was a naturally varying variable across classrooms. Structural models of children's spring print knowledge showed a significant interaction of dose and dose frequency in relation to children's outcomes. Follow-up analyses showed that the benefit of providing four versus two print-referencing sessions per week disappeared when teachers were providing a relatively intense number teaching strategies within sessions (i.e., the dose was high). Considered differently, findings also show that increasing the number of print referencing teaching strategies within a session (i.e., the dose) related positively to children's print knowledge development, but only when the weekly number of intervention sessions were low (i.e., two intervention sessions weekly). Overall, findings show that there is a benefit to increasing the dose or dose frequency of the print referencing intervention, but increasing both aspects of intervention intensity appeared to have a diminishing benefit to children's learning. Findings empirically support the multi-dimensional nature of intervention intensity and implications for research and practice are discussed.

► We related intensity of the print-referencing intervention to child outcomes.
► Dose (per session teaching) and dose frequency (sessions per week) measure intensity.
► A high-dose frequency enhanced learning only if dose was relatively low.
► Higher levels of dose related to more learning only when dose frequency was low.
► We find no added benefit to increasing both aspects of intervention intensity.