A group of people are followed over time to see who develops the disease.
A. They follow a sample/population over time,gather a group with condition and group without condition. Then compare exposure to risk factors and draw conclusions.
B. Follow population exposed to risk factor over time, split into group with condition and group without condition.
Follow popuation not exposed to risk factor, split into group with condition and group without condition. Then compare outcomes of all and draw conclusions.
a group of people who have the disease are compared with a group who don't have the disease.
They take histories of exposure to risk factors, compare and draw conclusions.