We analyzed two nationally representative, longitudinal data sets of U.S. children to identify risk factors for persistent mathematics difficulties (PMD). Results indicated that children from low socioeconomic households are at elevated risk of PMD at 48 and 60 months of age, as are children with cognitive delays, identified developmental delays…

Evidence to validate the use of fixed-time (FT) reinforcer delivery (i.e., noncontingent reinforcement) with typically developing populations has been relatively rare in the behavioral literature. In those studies that have provided validation, reinforcer delivery schedules appeared to be prohibitively dense for sustained implementation of…