Cohort studies are a type of observational research where a group of people, known as a cohort, is followed over time to observe outcomes related to specific exposures or risk factors. Researchers collect data on the cohort's characteristics and behaviors, allowing them to identify patterns and correlations between these factors and health outcomes, such as diseases or conditions. These studies can be prospective, where participants are followed into the future, or retrospective, where researchers look back at existing data. Cohort studies are valuable in understanding the long-term effects of exposures, helping to inform public health decisions and medical practices.