Identifying Research Methods in Psychology

In the realm of psychological research, distinguishing between different research methodologies is crucial for drawing valid conclusions. A researcher decides to examine the relationship between social anxiety and academic performance among college students. They choose to collect data via self-reported questionnaires that measure both the level of social anxiety and academic grades at the end of the semester. Later, the researcher wishes to establish how these two variables interact over a period of time, by tracking the same participants over several semesters. Which of the following research methods is the researcher primarily employing in this study?