Modelling Mortality in Kenya

John K. Njenga *

University of Nairobi, P.O. Box 13187 - 00200, Nairobi, Kenya.

Isaac C. Kipchirchir

Department of Mathematics, University of Nairobi, P.O. Box 30197 - 00100, Nairobi, Kenya.

*Author to whom correspondence should be addressed.


This research work seeks to analysis the mortality trend experienced in Kenya over the sample period 1950 to 2021 using a multidimensional modeling framework. Life table functions, namely; life expectancy, survival function and age at death distribution are applied to depict mortality characteristics. Life expectancy and survival rate have significantly improved. There has been a shift in mortality status from a high mortality population, to an intermediate stage and mortality risk factors have increased across age. Mortality concentration curve and index within the Lorenz curve and Gini coefficient framework are used to analyze the lifespan inequality. Lifespan inequality is high with negligible improvements over time. Gompertz force of mortality is then estimated, which is statistically significant at 5% level. Deaths at exact age 25 is about 35 per ten thousand, with the rate death rate increasing by 6.09% per year starting from age 25. Under the assumptions of stable population, where the mortality and fertility functions are independent of time, Malthusian parameter is estimated which is less than zero for selected years. Kenya is a shrinking population and death rate decrease with increase in Malthusian parameter. Finally, to model long-term mortality rate forecast, Lee-Carter model is estimated. The model is statistically significant at 5% level explaining 78.4% of the variations. Expected life expectancy at a given age is projected to increase, with life expectancy at birth in 2030 and 2071 being 65.6 and 70.5 years respectively.

Keywords: Life expectancy, mortality rate, life table, age specific mortality rate

How to Cite

Njenga, J. K., & Kipchirchir, I. C. (2024). Modelling Mortality in Kenya. Asian Research Journal of Mathematics, 20(1), 1–15.


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