Using the Organized Problem-Based Computation Intervention (OPBCI) to Support Arithmetic Word-Problem Solving in Fifth Graders with Learning Difficulties: A Single-Case Study

The present study investigated the use of the Organized Problem-Based Computation Intervention (OPBCI) within a single-case experimental framework. This instructional routine systematically employs graphic organizers to support arithmetic word-problem solving among students who require strategic assistance. Using a staggered multiple-baseline across-participants design, four fifth graders (two girls, two boys; aged 10-11) from a linguistically and socioeconomically diverse German lower-secondary school received 9-11 individual intervention sessions following baseline phases. Word-problem performance was measured using curriculum-based probes assessing correct identification of start, change, operation, and result quantities. Visual analysis and Tau-U indices indicated higher performance levels during intervention phases relative to baseline (τ = .57-.78). However, patterns of change varied across students and were, in some cases, constrained by baseline trends or ceiling effects. Social validity ratings were uniformly positive: students rated the OPBCI as useful, enjoyable, and easy to follow and reported that the graphic organizer supported their understanding of word-problem structure. Overall, the findings suggest that OPBCI may offer feasible, short-term instructional support for organizing arithmetic word-problem work in inclusive educational settings, while highlighting the need for cautious interpretation and further research.