The outcome could be anything from a mental or physical health condition or symptom (depression, cancer, coughing),
a behavior (violence, pro-social behaviors) or a psychometric measure (score on a test).
A risk factor is anything that is associated with an increase or decrease of the outcome.
It might be causal (as smoking is a risk factor for lung cancer) but may be just be correlated.
The term ‘risk factor’ is more common in observational studies, whereas in experimental studies
the terms ‘independent’ or ‘experimental’ variable may be more appropriate. The terminology doesn’t
matter:
as long as the study reports a relative risk, hazard ratio or odds ratio RealRisk will work. That’s because
they are all measures which quantify the change in outcomes between two groups. The condition that differs
between those two groups is what we are calling the
risk factor
.
Observational studies look at variation in a population without any intervention. For example,
researchers might track how much people normally eat or exercise and see if it associates with
health outcomes.
In experimental studies, the researchers are in control of the variation, as in a medical trial
where the researchers give one group a drug and the other a placebo.
