For over a century, teacher-centered learning occurred as the most prominent method of teaching students (Medve, 2023). The student-centered classroom provides students the opportunity to focus their learning on curriculum which is interesting to them. "Problem-Based learning (PBL) is a type of student-centered learning heavily influenced by constructivism" (Medve, 2023). According to Medve (2023), the purpose of this quantitative, quasi-experimental study was to explore if there is a difference in the academic achievement on norm-referenced and criterion-referenced assessment scores of students in a Central Florida high school who were taught in a PBL classroom as opposed to a traditional lecture-style classroom. This study investigated the differences in ninth and 10th- grade PBL versus traditional students' performance on norm-referenced and criterion-references assessments. Four research questions were asked in this study. Results indicated that ninth and 10th grade students enrolled in the PBL classroom had significantly higher scores on the criterion-referenced assessment (p = 0.023, and p = 0.0075, respectively) and on the norm-referenced assessment (p = 0.023, and p = 0.0065, respectively). Scores for the ninth-grade students on the norm-referenced assessment were inconclusive. "The conclusions drawn from this study indicate that students taught through PBL at this Central Florida high school have increased assessment results compared to their peers taught through traditional methods" (Medve, 2023). Implications from this study can be used to determine if additional research is needed in the various teaching settings based on the differences in the ninth and 10th-grade results on the norm- and criterion-referenced assessments. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]