Definicija: ge-standardisation adjusts rates to take into account how many old or young people are in the population being looked at. When rates are age-standardised, you know that differences in the rates over time or between geographical areas do not simply reflect variations in the age structure of the populations. This is important when looking at cancer rates because cancer is a disease that predominantly affects the elderly. So if cancer rates are not age-standardised, a higher rate in one country is likely to reflect the fact that it has a greater proportion of older people.