Sullivan’s method is a very simple method to compute health expectancies; it has been used and discussed by many authors. It combines data issued from a regular period life table on the one hand and from cross-sectional survey providing prevalence of a given health dimension on the other hand, let’s say, disability. The age-specific prevalence is directly applied to the person-year of the life table: it provides the total number of years spent with disability, the total number years lived without disability, and summing both, the total number of years lived.
Once the table is modified, the period life expectancy is calculated in the traditional manner, according to various states of disability. So, one can obtain a series of total life expectancy, disability-free life expectancy and life expectancy with disability.
Cross sectional survey often exclude people living in institution among which many persons with disability: in the original Sullivan methods, the person-years of the life tables where divided into years lived in household and years lived in institution (based on population census data). The years lived in household where shared in years with and years without disability as described above. Years lived in institution were considered as years lived with disability. More precise data allow to be more close to the real prevalence of disability within institution to better estimate the disability free life expectancy.
The main advantage of the Sullivan’s method lies in the separate collection of mortality and disability data and in the ready availability of the data necessary for the calculation. Basic cross-sectional surveys are sufficient to collect the observed prevalence of disability within the population. However the problem with this method lies in approximating the period prevalence by the observed prevalence of disability.
For further information, you can download documents on this website:
- Calculation guide
- Sullivan methods computation spreadsheet
A computation moduleis available on EuroHex, the website devoted to the European health expectancies on a click
Sullivan DF. A single index of mortality and morbidity. HSMHA Health Rep 1971;86:347-354. 11