When conducting a study, patients occasionally “crossover” to other portions of

When conducting a study, patients occasionally “crossover” to other portions of the study. List one intervention that may impact the patient after this crossover, how it might affect the results of the study, and which (if any) precautions need to be considered when finding crossover data. Additionally, explain what a cohort study is and which types of disease are best to study using a cohort.