Impact of Inquiry-Based Learning on Science Reasoning in Secondary Schools

Thesis Abstract

This study investigates how Inquiry-Based Learning (IBL) influences science reasoning development among secondary school students, addressing persistent gaps in reasoning skills despite curricular emphasis on scientific inquiry. The problem centers on limited empirical evidence linking classroom-implemented IBL to measurable enhancements in argumentation, evidence evaluation, and hypothetical-deductive reasoning within science disciplines. The aim is to determine the impact of a structured IBL program on students’ science reasoning levels and to identify contextual factors that moderate or mediate this relationship. Specific objectives are (1) to compare pre- and post-intervention science reasoning scores between students exposed to IBL and those taught via traditional methods; (2) to examine changes in specific reasoning subskills—hypothetical-deductive reasoning, probabilistic reasoning, and evidentiary evaluation; (3) to explore teachers’ fidelity to IBL protocols and classroom practices; (4) to assess whether student engagement, collaborative discourse, and perceived autonomy predict reasoning gains; and (5) to examine potential moderating effects of prior achievement and gender on the IBL–reasoning relationship. The study adopts a quasi-experimental, mixed-methods design conducted in six public secondary schools within a metropolitan district. Two schools implement a 12-week, standards-aligned IBL module across biology and chemistry, while two matched schools continue with conventional didactic instruction, and two additional schools serve as a staggered IBL group to control for maturation effects. The population comprises approximately 2,400 students in grades 9–11; a stratified random sample of 1,200 students (approximately 200 per school) participates, with intact class groups retained to preserve instructional fidelity. Data collection instruments include (a) the Lawson Classroom Test of Scientific Reasoning (LCTSR) as the primary quantitative measure of science reasoning, administered at baseline (week 0) and post-intervention (week 12); (b) a validated Science Inquiry Attitudes Scale to gauge engagement and disposition; (c) a Student Discourse Analysis Protocol to quantify quality of argumentative discourse during laboratory activities; (d) classroom observation checklists aligned with the IBL framework to assess fidelity; and (e) teacher interviews and a Fidelity Rating rubric to capture implementation consistency. Data analysis employs a multi-tier approach descriptive statistics and reliability checks for all instruments; repeated-measures ANOVA to test differences in LCTSR gains between groups, controlling for baseline scores; multilevel modeling to account for nested data (students within classes within schools) and to test moderator effects of prior achievement and gender; multiple regression analyses to identify predictors of reasoning gains (engagement, discourse quality, and autonomy). Qualitative data from discourse analyses and teacher interviews will be analyzed using thematic coding and triangulated with observation data to illuminate mechanisms by which IBL influences reasoning. Expected findings include statistically significant improvements in post-test LCTSR scores for students in the IBL condition relative to the traditional instruction groups, with moderate effect sizes (Cohen’s d around 0.40–0.60). Subskill analyses are anticipated to reveal larger gains in hypothetical-deductive reasoning and evidentiary evaluation for IBL learners, driven by structured inquiry prompts, argumentation dialogs, and collaborative problem-solving tasks. Fidelity analyses are expected to show a positive association between higher adherence to IBL protocols and magnitude of reasoning gains. Qualitative findings are anticipated to illuminate processes such as scaffolded questioning, iterative hypothesis testing, and peer critique as core mechanisms enhancing cognitive engagement and reasoning sophistication. The study contributes to knowledge by providing rigorous, contextually grounded evidence on the effectiveness of IBL in developing science reasoning in secondary education, clarifying which components of IBL most strongly predict reasoning gains, and identifying classroom practices and teacher supports essential for successful implementation. The findings will inform policy and professional development, offering actionable recommendations for integrating IBL with district curricula to strengthen reasoning-focused competencies. The conclusion will emphasize that well-implemented IBL can produce meaningful improvements in science reasoning, particularly when complemented by ongoing teacher professional learning, robust assessment of discourse quality, and mechanisms to sustain student autonomy and collaborative inquiry beyond pilot interventions. Recommendations include scaling up IBL with explicit fidelity guidelines, embedding formative reasoning assessments, and providing structured PD that emphasizes strategic questioning, argumentation, and reflective practice to maximize student outcomes in science reasoning.