Example: The more years of education a person receives, the higher his or her yearly income is.

A negative correlation (–) means that when one variable increases, the other one decreases.

Example: The more hours a high school student works during the week, the fewer A’s he or she gets in class.

The higher the correlation coefficient, the stronger the correlation. A +0.9 or a –0.9 indicates a very strong correlation; a +0.1 or a –0.1 indicates a very weak correlation. A correlation of 0 means that no relationship exists between two variables.

Common correlational research methods include case studies, surveys, naturalistic observation, and laboratory observation.

Case Studies

In a case study, a researcher studies a subject in depth. The researcher collects data about the subject through interviews, direct observation, psychological testing, or examination of documents and records about the subject.

Popular pages: Research Methods in Psychology