Constant Time Delay and System of Least Prompts: Efficiency and Child Preference

Abstract

Prompting procedures are effective for teaching skills, but limited comparative data exist to guide practitioners to select the best procedures for individuals. This study compared efficiency of two prompting procedures—constant time delay (CTD) and system of least prompts (SLP)—to teach expressive identification of 32 targets to 10 preschoolers with and without disabilities. To assess efficiency differences between conditions and analyze changes in learning over time, we used adapted alternating treatments designs in the measurement context of cumulative records. CTD was more efficient for five children, SLP was more efficient for three children, and results were inconclusive for two children. We measured children’s choices between procedures via simultaneous treatments designs, to assess child preference and whether preferences and efficiency aligned. Preference outcomes were mixed and did not consistently align with efficiency. We used exploratory analyses to assess whether child characteristics moderated outcomes. Children for whom CTD was more efficient had significantly fewer sessions to mastery, non-significantly fewer errors, and non-significantly higher developmental assessment scores, compared to children for whom SLP was more efficient.