ABSTRACT
A lthough it may be tempting to try to understand people’s behavior and opinions with just one simple explanation or cause, in reality there are mul-tiple reasons for those beliefs and actions. Understanding more about how your variables work together in explaining behavior and attitudes is essential for doing quality research. If, for example, you are trying to understand why students’ grades vary, the number of hours studying is probably just one reasonable answer. What else might explain differences in grades? Quality of the instructor, test-taking abilities, physical and mental health of the people at the time of doing the required work or test, difficulty of an assignment, basic intelligence levels, and the party the night before are all plausible alternative explanations.
