Correlation research is a type of non-experimental research method. It is used to determine whether, and if so to what degree, a relationship exists between two or more variables.
In this type of research, if the change in one variable triggers a change in another, one could hypothesize that there is a relationship between both variables.
Yet, it does not establish cause and effect, but rather identifies patterns of association.
Correlation could be positive, negative, or non-existent (zero correlation). If the researched variables increase or decrease together, it is called positive correlation; if they move in the opposite directions, a negative correlation; and in case the movement of one does not affect the other, zero correlation.
Naturally, such research usually involves a vast amount of statistical data.
Correlation Research is used in media studies, audience research, and communication behavior analysis.