Confound definition | Psychology Glossary

Confounding in psychology is when an external, unaccounted-for variable might influence the results. In an ideal study, the only variables that should influence the results are the ones being controlled for. When a study is conducted and a researcher isn’t aware or doesn’t stop another variable affecting the results, the study can’t be said to have a certainty of cause and effect. A study can be considered internally valid, or to have internal validity, when all of the extraneous variables are thought to be controlled, accounted for, or eliminated.

It can be a big problem in studies of lifestyle and diets as there are nearly countless variables that can affect subjects. Much like why, after eating Halloween candy all year, taking vitamin C doesn’t seem to have cured me of gluttony. Or something like that.