Cause to effect progression is seen in all EXCEPT-
a case control study is always employed in such diseases where an exposure and outcome had already occurred.it is a retrospective kind of study in which the study always progresses from effect to cause. ref:park&;s textbook of preventive and social medicine,22nd edition,pg no 71
Case control study
Ecological study
Coho study
Randomized control trail
Epidemiology