The Absolute Risk

Relative Risks are only part of the overall picture. For example, if a certain illness is caused in one in 10 million women, the fact that the relative risk has increased by a factor of two (to one in 5 million women) is irrelevant - one's chances of ever contracting this symptom are almost zero, and way lower than the many other risks that face us. To understand the actual risk, we need to know the frequency with which the illness will occur.

We will use the term "Absolute Risk" (AR) as follows:
Imaging you are a member of a group of 100 women. All the women have similar characteristics such as age and general health. Over a period of 10 years, a few of the women will develop a certain illness (a heart problem, cancer, fracture, etc.). The number of women (out of the 100) that become ill throughout the ten-year period is defined as the "Absolute Risk".

Another approach is to consider how long (how many years) it takes a certain number (e.g., 10) out of a group of 100 women to become ill:
If the risk is increased, it will take a shorter time till the 10 women become ill; if it is decreased, it will take longer. (The choice of the number 10 is arbitrary!).