This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Epidemiological Study, Subject name: Social & Preventive Medicine
Cause to effect progression is seen in all EXCEPT: 
Select and explain. 
A. Case control study, B. Ecological study, C. Cohort study, D. Randomized control trial
A: Case control study
Answer: A: Case control study 
Explanation: ANSWER: (A) Case control studyREF: Park 20th edition page 67 Repeat in December 2011Cause to effect (disease) = prospective study (cohort study)Effect (disease) to cause = retrospective study (case control study)RCT and ecological studies are also prospective studies