We assume that, at a certain period of time (for example, a given year), every living individual of a population on which we want to calculate the Sullivan indicator can be unambiguously described as being in exactly one of a fixed number of states of health.

Consider a collection of individuals classified in increasing *W*+1
age groups (numbered from *i*=0 to *i*=*W*) and a particular health
state which has been located on some of them. Suppose you want to
have a health indicator on the whole population which doesn't depend
on its age structure. Using a common notation [4], let:

- =number of survivors of age (beginning of the age
interval
*i*). In other words, it is assumed that of every persons alive at age will survive until age . - =number of person years (see section 3.2.1) lived in the
age group
*i*. That is to say the number of years lived by the persons in the interval*i*. Each member of the cohort who survives the interval*i*contributes to , each member of the cohort who have died during the interval*i*contributes only a part of that time. - =prevalence of the particular health state for age group
*i*(that is to say the percentage of persons in this health state in the whole population of the age interval*i*).

The health state indicator proposed by Sullivan can be calculated as:

Values of can be estimated from a cross-sectional health survey on the whole population. and are provided by an ordinary current life table.

Fri Apr 25 22:40:35 DFT 1997