the rand future elderly model came the closest by testing the potential future impact of the introduction of new technologies on both population health status and direct health care expenditures the first is known as the dynamic equilibrium or healthy ageing hypothesis it assumes that the morbidity period prior to death remains unchanged as life expectancy increases so that each year gained in life expectancy corresponds to an equal increase in years of healthy life the second is a pessimistic view called expansion of morbidity where by increases in life expectancy yield a longertime spent with illhealth and reduced quality of life