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Randomized Trials - Answer (type of experimental study); how epidemiologists investigate
whether one intervention (treatment, vaccine, etc.) is better than another.
Experimental Studies - Answer investigators are responsible for assigning study participants to
groups and intervening in some way (ex. Exposing them to an exposure of interest,
administering a treatment of some sort, etc.)
What are the 2 Main forms of Experimental Studies? - Answer 1) Lab experiments (clinical
trials)
2) Field experiments (field trials)
Lab Experiments (randomized clinical trials) - Answer look at disease in a controlled, clinical
environment. Often carried out in hospitals or other clinical setting where the subjects are
treated and followed up for their condition.
"Challenge Trial" - Answer a type of clinical trial; Instead of subjects receiving a treatment, the
subjects are exposed to a given exposure of interest such as a virus.
What is the Main Advantage of Clinical Trials - Answer the study takes place in a highly
controlled environment, where potential cofounders or other factors can be controlled, and the
frequency and dose of the challenge/exposure can be set.
What is the Main Disadvantage of Clinical Trial - Answer does not consider a number of
factors/exposures that are present in a real-world scenario, therefore, further studies (usually in
the field) are required.
Field Experiments (randomized field trials) - Answer look at disease in a real-world scenario;
subjects are entered in the trial if they are free of disease at the time of enrollment, then the
treatment or procedure of interest is evaluated to see if it reduces the risk of the subjects
developing the disease in the future.
What is the Main Advantage of Field Experiments - Answer real-world setting; field trials allow
investigators to assess the impact of various treatments in the settings in which they will be
applied to future individuals, thereby establishing relevance.
What is the Main Disadvantage to Field Experiments - Answer logistically more difficult to
carry out because they involve healthy people rather than diseased people. Many may develop