Question

What is the difference between observational studies and experiments? Be sure to discuss/explain control of confounding variables, bias, and the pros and cons of each method.

Answer 1

In an experiment, researcher/experimenter apply treatments to experimental units (people, animals, plots of land, etc.) and then proceed to observe the effect of the treatments on the experimental units.

In an observational study, researcher/experimenter observes subjects and measure the variables of interest without assigning treatments to the subjects. The treatment that each subject receives is determined beyond the control of the investigator.

experiment pros & cons

pros:
(i) treatments are assigned
(ii) effects are measured
(iii) the researcher has full control (less vulnerable)
Cons:

(i) the experiment can fail (ii) time-consuming (iii) more biased because subjects are assigned

Observational study Pros &cons

Pros:

(i) treatments occur naturally
(ii) unbiased because subjects are grouped naturally
(ii) less time consuming
Cons:
(i) The researcher has no control (more vulnerable)
(ii) can be viewed too subjective
(iii) difficult to establish clear results