Which among the following is the major practical problem in a coho study?
Disadvantages of coho studies: Have to follow large numbers of subjects for a long time. They can be very expensive and time consuming. They are not good for rare diseases. They are not good for diseases with a long latency. Differential loss to follow up can introduce bias.
Differential loss of follow up
Long duration of study
Can be used only for rare conditions
None of the above