“Interleaving Retrieval Practice…” Study By Sana & Yan


The study investigated the long-term effects of interleaved retrieval practice in ninth- through 12th-grade science classrooms. The essay provides an in-depth analysis of the study, demonstrating its efficiency in light of the applied research design, validity, and conclusions. It covers various aspects of the text, including a description of the participants, research design, variables investigated and how they related to each other, ethical issues associated with the study, validity, and reliability, and the research findings.


The participants were 155 students from a midsize Canadian public high school in southern Ontario. Most of the respondents had an English origin, accounting for 61% of the study’s total sample population (Sana & Yan, 2022). The learners were randomly selected and given a Tim Horton’s gift card worth $3 to complete a consent form to encourage them to participate in the study willingly. A total of six teachers engaged in the study, all teaching chemistry, biology, or physics. The tutors were selected through a workshop to identify the techniques that best enhance student learning.

Research Design

The study used an experimental design in the form of a repeated measures technique, entailing three variables. In this design, the same participants are involved in every experiment variable. This is usually done to control individual differences since it is assumed that any differences between the participant’s scores on the dependent variable are due to experimental manipulation and not other factors. The three variables used in this design are unpracticed concepts (control), interleaved concepts, and practice-blocked concepts (Sana & Yan, 2022). In this research, the investigators looked at the effect of interleaving retrieval practice on science learning in the classroom setting. This allowed them to see how the students responded to the quizzes and the final test in a real-world environment.

Variables of Interest

The primary variables investigated based on conceptual definitions include retrieval practice, interleaving, learning gains and long lasting conceptual understanding. On the other hand, variables in terms of operational definitions are test performance, weekly and final examinations and order of questions provides, whether interleaved or blocked. The study variables are the concepts taught each week, the quizzes administered, the final test, and the students’ performance on the quizzes and final test. The independent variable is the type of quiz which may be blocked or interleaved and the dependent variable is the students’ performance on the final test. The no-quiz control condition was the control variable, while the mediator variable is the students’ performance on the quizzes.

Validity and Reliability Critique

The reliability of the operational definitions may be problematic because a person can’t tell whether the quiz questions represent the concepts taught in the class. There is a possibility that the questions on the quiz may not be representative of the entire concept or that the questions may be more complicated than the average concept taught in class. The construct validity of the operational definitions may also be problematic because it is challenging to identify whether the quiz questions measure the concept of interest (Sana & Yan, 2022). The quiz questions have targeted entirely different ideas, or the questions may not be sensitive enough to measure the concept of interest.

The internal validity may also be questionable because it is difficult to determine whether the quiz questions are causing improved performance on the final test. The improved performance on the final examination may be due to other factors, such as prior knowledge or motivation. There could be an error with the study’s external validity because it is hard to establish whether the study results can be generalized to other populations. It is possible that the study results are specific to the population studied and may not generalize to other populations.

Results and conclusions

The study found that interleaved retrieval practice leads to better performance on a final test than blocked retrieval practice. This finding suggests that interleaving concepts during retrieval practice can help students learn and remember concepts better than if they had focused on one concept at a time. The study found that students performed better on ideas in the interleaved quizzes, where the order of the questions was mixed up, than on concepts in the blocked examinations, where questions were organized by concept (Sana & Yan, 2022). The data shows a significant difference in performance on the final test for the interleaved-retrieval-practice condition compared to the control and blocked-quiz conditions.

The internal validity of the study faces some potential threats. First, the concepts taught in each week were not randomly assigned to the interleaved or blocked-quiz conditions; rather, randomization of concepts to condition occurred on a weekly basis for each course-grade combination. Second, there was no random assignment of interleaved- or blocked-quiz conditions to learners; rather, the teacher in each classroom determined which condition the students in that class would be in. Lastly, the study lacked a guiding condition for the no-quiz control (Sana & Yan, 2022). As a result, one cannot rule out the possibility that the improved performance on the final test in the interleaved-quiz condition was due to the fact that the students were simply taking more quizzes, not because of the interleaving itself.

Ethical issues

One ethical issue that could be relevant to this study is informed consent. It is unclear clear from the information provided whether the students and their guardians were fully informed of the study procedures and potential risks and benefits before consenting to participate. Another issue that could be relevant is the use of deception. It is possible that the students were not told the study’s true purpose and that the study was presented to them as simply a series of quizzes. If this is the case, the students may have felt deceived and misled by the researchers.


Sana, F., & Yan, V. X. (2022). Interleaving retrieval practice promotes science learning. Psychological Science, 33(5), 782–788.