Risk factor  In epidemiology, a risk factor or determinant is a variable associated with an increased risk of disease or infection. Determinant is often used as a synonym, due to a lack of harmonization across disciplines, in its more widely accepted scientific meaning. Determinant, specific to community health policy, is a health risk that is general, abstract, pertains to inequalities and is difficult for an individual to control. For example, low ingestion of dietary sources of vitamin C is a known risk factor for developing scurvy. Poverty, in the discipline of health policy, is a determinant of an individual's standard of health. The main difference lies in the realm of practice, clinical practice versus public health. Risk factors or determinants are correlational and not necessarily causal, because correlation does not prove causation. For example, being young cannot be said to cause measles, but young people have a higher rate of measles because they are less likely to have developed immunity during a previous epidemic. Statistical methods are frequently used to assess the strength of an association and to provide causal evidence (for example in the study of the link between smoking and lung cancer). Statistical analysis along with the biological sciences can establish that risk factors are causal. Some prefer the term risk factor to mean causal determinants of increased rates of disease, and for unproven links to be called possible risks, associations, etc. When done thoughtfully and based on research, identification of risk factors can be a strategy for medical screening. Mainly taken from risk factors for breast cancer, risk factors can be described in terms of, for example:  The following example of a risk factor is described in terms of the relative risk it confers, which is evaluated by comparing the risk of those exposed to the potential risk factor to those not exposed. Let's say that at a wedding, 74 people ate the chicken and 22 of them were ill, while of the 35 people who had the fish or vegetarian meal only 2 were ill. Did the chicken make the people ill? So the chicken eaters' risk = 22/74 = 0.297 And non-chicken eaters' risk = 2/35 = 0.057. Those who ate the chicken had a risk over five times as high as those who did not, that is, a relative risk of more than five. This suggests that eating chicken was the cause of the illness, but this is "not" proof. The probability of an outcome usually depends on an interplay between multiple associated variables.