What is a crucial disadvantage to correlational research?

A crucial disadvantage of correlational research is that it cannot establish cause-and-effect relationships. A correlational study examines the possible relationship between two or more variables. However, unlike a true experiment, the researchers do not manipulate variables; rather, they investigate naturally occurring or pre-existing variables.

As such, correlational studies suffer from the directional problem, which refers to the difficulty in determining which variable is causing a change in the other. For example, does having a “good memory” cause a person’s hippocampus to be larger, or does having a larger hippocampus result in stronger memory? The directional problem is sometimes referred to as bidirectional ambiguity. Bidirectional ambiguity raises a broader question about whether two variables might be influencing each other simultaneously through mutual interaction.

A further problem with correlational research is that researchers cannot rule out the possibility that a third variable, a confounding or extraneous factor, is responsible for the observed relationship.