Cohort, cohort study: Studies that follow subjects over time and collect information before subjects becomes cases. Therefore, a temporal order can be assessed and recall bias is not a problem. However, caution needs to be taken in implying causality because the investigators don't have control over who has the potential risk or protective factors of interest. It is oftentimes used to study eating disorders as it would be unethical to randomly assign participants to clinical trials that would potentially increase their vulnerability towards developing an eating disorder.