What are indices and how are they interpreted?
For any particular attribute or characteristic (e.g. use of mobile phones or attendance at private hospitals) you may need to understand and compare the pattern of its representation within a target population group (e.g. adults who use mobile phones or people who attend private hospitals) with the pattern in another larger group usually called the base population group (e.g. all adults or the total population). The Index value is computed by relating the target to your chosen base as follows: where: n = the count of people/households with a characteristic in geodemographic cluster k K = the total number of geodemographic clusters N = the count of people/households in geodemographic cluster k Indices tell you how far above or below the national average value an area is for an observed attribute. The national average value for the indices is 100; therefore an area with an index of 200 is twice the national average while an area with an index of 50 is half of the national average. For in
