Life expectancy at birth measures the average number of years that a newborn baby can expect to live. Life expectancy statistics are used for many purposes of annual assessment of world health. However, life expectancy (LE) estimates are based on the overall length of life based on mortality data only.
What Is DALE? DALE is disability-adjusted life expectancy, developed by WHO in 1999, which measures the equivalent number of years of life expected to be lived in full health, also called healthy life expectancy. To calculate DALE, the years of ill-health are weighted according to severity and subtracted from expected overall life expectancy to give the equivalent years of healthy life. Following is the formula used to estimate DALE: DALE = LE – DLE. Where LE is total life expectancy based on average numbers of years males and females could expect to live in each country. DLE is expected years lost due to disability – an estimate of the total equivalent lost of years of good health.
Why healthy life expectancy? Life expectancy at birth increased dramatically during 20th century and will continue to rise as soon as cancer and other life-threatening diseases are conquered. However higher life expectancy is desirable only if it is linked to acceptable level of quality of life. With a longer life span the subject of healthy years of life to be lived has become an important issue. Sociologists and other scientists of every country are interested higher level not only life expectancy, but also years of healthy life. Hence disability-adjusted life expectancy, DALE has become more salient. Today DALE indicator is widely used sociological tool.
Health outcomes, in terms of DALE, is directly linked to access to medicines (The World Medicines Situation 2004). In recognition of present day need, the DALE indicator developed by WHO is an important sociological tool and it will further promote analysis of health performance of poorly performing health systems of the world.