Abstract:
Population ageing is an universal phenomenon and it is expected to be among the most
prominent global demographic trends of the 21st century. In Sri Lanka there was a rising
trend of ageing population throughout the past years and has recorded the highest
number of agers within South Asia. However, no sound statistical or mathematical models
were developed to project ageing population in Sri Lanka. Using the population aged 60
years and above in Sri Lanka during 1950-2016, three types of statistical models: (i)
ARIMA (0, 2, 1), (ii) exponential trend model, and (iii) double exponential smoothing
model were developed. The models were compared using various statistical indicators
and some statistical diagnostics tests. The comparison was done for both training set as
well as validation set. Among these models the double exponential smoothing model was
found as the best fitted model. According to the forecast derived from the best fitted
model, it was found that the increasing trend of ageing population in the country will
continue in the future and there will be approximately 2,936,000 ageing population in Sri
Lanka in 2020. The information obtained from this study is beneficial for planners and
decision makers in the government sector and other relevant organizations to cater the
needs of the increasing agers in the future of Sri Lanka.
