Canadian students experience many different assessments throughout their schooling (O'Connor 2011). There are many benefits to using a variety of assessment types, item formats, and science-based performance tasks in the classroom to measure the many dimensions of science education. Although using a variety of assessments is beneficial, it is unclear exactly what types, format, and tasks are used in Canadian science classrooms. Additionally, since assessments are often administered to help improve student learning, this study identified assessments that may improve student learning as measured using achievement scores on a standardized test. Secondary analyses of the students' and teachers' responses to the questionnaire items asked in the Pan-Canadian Assessment Program were performed. The results of the hierarchical linear modeling analyses indicated that both students and teachers identified teacher-developed classroom tests or quizzes as the most common types of assessments used. Although this ranking was similar across the country, statistically significant differences in terms of the assessments that are used in science classrooms among the provinces were also identified. The investigation of which assessment best predicted student achievement scores indicated that minds-on science performance-based tasks significantly explained 4.21% of the variance in student scores. However, mixed results were observed between the student and teacher responses towards tasks that required students to choose their own investigation and design their own experience or investigation. Additionally, teachers that indicated that they conducted more demonstrations of an experiment or investigation resulted in students with lower scores.