Assessing the Impact of Problem-Based Learning on Conceptual Understanding and Scientific Literacy in High School Biology Students

Project Abstract

This study investigates how problem-based learning (PBL) influences conceptual understanding and scientific literacy among high school biology students, with a mixed-methods design conducted across three public schools over an academic year. The quantitative strand employed a quasi-experimental design, involving two parallel classes (PBL and traditional instruction) in each school, totaling six biology sections and approximately 240 students. Pretests and posttests assessed domain-specific conceptual understanding using validated biology concept inventories and instruments measuring scientific literacy, including the ability to interpret data, evaluate claims, and communicate scientific arguments. Additionally, retention was examined through a follow-up assessment three months post-intervention. Statistical analyses included ANCOVA to control for prior achievement, effect size calculations, and multilevel modeling to account for nesting within classes and schools. The qualitative strand collected classroom observations, think-aloud protocols during problem-solving tasks, and semi-structured interviews with teachers and a stratified sample of students to explore cognitive processes, motivation, and attitudes toward science. Thematic analysis of transcripts and triangulation with observation notes provided insights into the mechanisms by which PBL enhances or constrains learning outcomes. Results indicate that students in the PBL condition exhibited significantly greater gains in conceptual understanding, particularly in systems biology, genetics, and ecology, compared to peers in traditional instruction (p < 0.01, large effect size). Scientific literacy scores also improved more markedly in the PBL group, especially in evaluating evidence and constructing coherent explanations, with notable gains in classroom discourse quality and argumentation skills. Retention effects suggested that PBL fosters durable understanding, as post-intervention gains persisted at the three-month follow-up. Qualitative data revealed that PBL promoted deeper engagement, greater use of metacognitive strategies, and enhanced collaboration, though challenges emerged related to time management, scaffolding for students with limited prior knowledge, and the need for explicit instruction in epistemic authority and scientific writing. Teachers reported that well-designed PBL tasks aligned with curriculum standards, supported by rubrics and formative feedback, were critical for success, while student variability in self-regulation required targeted support. The study discusses implications for curriculum design, teacher professional development, and assessment practices, advocating for structured PBL frameworks, explicit instruction in scientific inquiry, and formative assessment loops that continually calibrate task difficulty to learners’ readiness. Limitations include potential instructor effects, variability in classroom resources, and the generalizability limited to similar urban educational contexts. Recommendations for future research emphasize longitudinal tracking across multiple cohorts, exploration of digital PBL adaptations, and investigation of differential impacts across student subgroups. Overall, the findings support the adoption of PBL as a potent instructional approach to enhance both conceptual mastery and scientific literacy in high school biology, contributing to a more inquiry-driven science education paradigm.

Project Overview

What This Project Is About

---

A plain-language overview of the topic and what the project investigates.

---

---

The Problem It Addresses

---

What problem or gap this project tackles and why it matters to the field or society.

---

---

Objectives of the Project

---

1. Define how Problem-Based Learning (PBL) is used in high school biology classes.
2. Measure changes in students’ conceptual understanding after PBL activities.
3. Assess improvements in scientific literacy, including ability to interpret data and reason scientifically.
4. Compare PBL with traditional teaching methods to see which better supports learning goals.
5. Identify practical challenges teachers face when implementing PBL in biology.

---

---

What You Will Do Step by Step

---

1. Review relevant literature on PBL, biology education, and scientific literacy.
2. Design PBL activities aligned with biology topics and learning standards.
3. Recruit volunteer classes and obtain ethical approval if required.
4. Pre-test students to gauge baseline conceptual understanding and literacy.
5. Implement PBL units in selected classes over a term.
6. Post-test using the same assessments to measure learning gains.
7. Analyze data to compare pre- and post-test results and between groups.
8. Summarize findings and reflect on practical classroom implications.

---

---

Expected Outcome

1. Evidence on whether PBL improves conceptual understanding in biology.
2. Evidence on whether PBL enhances scientific literacy skills.
3. Insights into feasible implementation strategies and teacher support needs.