1. A

    age structure

    The relative number of people in each age group in a population.

    age-specific rate

    A rate for a specific age group. The numerator and denominator relate to the same age group.

    age standardisation

    A way to remove the influence of age when comparing populations with different age structures. This is usually necessary because the rates of many diseases vary strongly (usually increasing) with age. The age structures of the different populations are converted to the same 'standard' structure, and then the disease rates that would have occurred with that structure are calculated and compared.

  2. D

    data linkage

    The bringing together (linking) of information from 2 or more different data sources that are believed to relate to the same entity (for example, the same individual or the same institution). This linkage can yield more information about the entity and, in certain cases, provide a time sequence – helping to 'tell a story', show 'pathways' and perhaps unravel cause and effect. The term is used synonymously with 'record linkage' and 'data integration'.