Impact of Inquiry-Based Learning on High School Science Achievement Across Demographics

Thesis Abstract

This study investigates how Inquiry-Based Learning (IBL) influences high school science achievement across diverse demographic groups, addressing concerns that traditional didactic approaches may perpetuate achievement gaps along gender, socioeconomic status, and ethnicity. The aim is to determine whether IBL enhances overall science performance and whether its effects vary by demographic subgroups. Specific objectives include (1) assessing the effect of an IBL-oriented curriculum on end-of-term science achievement tests, (2) examining differential effects of IBL across gender, SES, and ethnic groups, (3) exploring changes in students’ science attitudes and self-efficacy as potential mediators, and (4) evaluating teacher fidelity to IBL protocols and its relation to outcomes. The study is grounded in constructivist learning theory and social-constructivist perspectives on collaborative inquiry, with Kolb’s experiential Learning Cycle guiding interpretation and Vygotsky’s zone of proximal development informing instructional design. A mixed-methods approach combines quantitative assessment with qualitative insights to capture both performance and experiential dimensions of learning. A quasi-experimental design with a pretest–posttest non-equivalent groups structure was employed in two comparable urban high schools with similar baseline achievement and demographic compositions. The population comprises 10th-grade biology and chemistry cohorts (n ? 420 students; 210 in the IBL condition and 210 in the traditional instruction condition) over a full academic year. Sampling used matched-pair assignment at the classroom level to preserve instructional feasibility while balancing demographics. Data collection instruments include (i) a standardized science achievement test aligned with national curriculum benchmarks, administered at baseline and post-intervention; (ii) a validated science attitude and self-efficacy scale administered at mid-year and post-intervention; (iii) an instructional fidelity checklist completed by trained external observers across biweekly cycles; (iv) a short demographic questionnaire capturing gender, SES indicators (parental education and free/reduced lunch status), and ethnicity. Reliability analyses yielded Cronbach’s alpha > .85 for the achievement and attitudinal measures. Validity was supported by content validity reviews and pilot testing. Quantitative data will be analyzed using Analysis of Covariance (ANCOVA) to compare post-test achievement scores between IBL and control groups while covarying baseline achievement. Multigroup analyses will assess interaction effects between teaching condition and demographic variables (gender, SES, ethnicity). Mediation analysis will test whether changes in science attitudes and self-efficacy mediate the relationship between instructional approach and achievement. Regression diagnostics will ensure assumptions of linearity and homoscedasticity. Latent growth modeling will be considered if sufficient repeated measures are available. Qualitative data from teacher logs, classroom observations, and focus groups with students will be analyzed using thematic analysis to identify patterns of engagement, collaboration quality, and perceived relevance of inquiry tasks. Triangulation will integrate quantitative and qualitative findings to illuminate mechanisms by which IBL may reduce or exacerbate achievement gaps. Expected findings include higher post-intervention achievement in the IBL condition relative to traditional instruction, with effect sizes in the small-to-moderate range (Cohen’s d ? 0.25–0.45). It is anticipated that IBL will yield more pronounced gains among students from lower SES backgrounds and certain ethnic groups, moderated by instructional fidelity and student collaboration quality. Positive shifts in science attitudes and self-efficacy are expected to partially mediate achievement gains. The study is likely to reveal that high-fidelity, well-structured inquiry tasks fostering equitable participation produce the most substantial improvements, while lower fidelity may not yield significant effects. The contribution to knowledge lies in providing empirical evidence on the scalability and equity implications of IBL in urban high schools, clarifying how demographic factors interact with inquiry-based practices, and identifying fidelity thresholds necessary to realize educational benefits. The findings will inform teacher professional development, curriculum design, and policy decisions regarding science instruction that aims to close achievement gaps. The study concludes that when implemented with rigorous fidelity and culturally responsive scaffolding, IBL can enhance science achievement for diverse learners and contribute to a more inclusive science educational landscape. Recommendations include targeted professional development for teachers on equitable collaborative planning, collaboration-friendly classroom routines, and ongoing monitoring of fidelity and student affect to sustain positive outcomes.