Comparing instructional uncertainty and deterministic instruction in reading comprehension: Effects on decision consistency and motivational fluctuation

This mixed-methods quasi-experimental study sought to compare an instructional uncertainty approach with a deterministic instructional approach in a 16-week undergraduate reading comprehension course at a public university in China. Although 96 students from two intact classes were initially recruited, the Oxford Quick Placement Test was used to identify those within the designated proficiency band, resulting in a final analytical sample of 83 participants, with 41 assigned to the instructional uncertainty condition and 42 to the deterministic instructional condition. Both classes were taught by the same instructor, received equal instructional time, studied comparable materials, and completed reading tasks of similar difficulty. Quantitative data were obtained through validated scales, while two trained observers conducted structured non-participant observations at different stages of the intervention. Between-condition and within-condition comparisons were used to examine the quantitative data, and the observational records were analyzed through directed comparative qualitative content analysis. The findings indicated that both instructional approaches supported improvement, although instructional uncertainty produced greater gains in decision consistency and overall motivational development. Students in this condition increasingly used textual evidence to justify retaining or revising their interpretations and showed task-level changes in hesitation, confidence, attention, persistence, and renewed engagement. By contrast, deterministic instruction promoted steadier participation and procedural consistency but was more often associated with dependence on modeled strategies and immediate confirmation. The evidence supports the conclusion that reading instructors should integrate bounded uncertainty with graduated guidance, evidence-based discussion, and timely resolution. Reading curricula and assessments should likewise recognize justified revision and motivational recovery as signs of adaptive learning rather than regard every change in response or motivation as a deficiency.