Predictions of Malaysia Age-Specific Fertility Rates using the Lee-Carter and the Functional Data Approaches

Abstract

Global fertility has been experiencing a significant
decline, reaching towards the replacement ratio. This trend,
coupled with increasing life expectancies, has led to the emergence
of an ageing population. In this study, we aim to analyse fertility
patterns among Malaysian women, considering both their
childbearing age and ethnicities. A 63-year age-specific fertility
dataset, from 1958 to 2020, were collected from the Department of
Statistics Malaysia. These data were fitted into the Lee-Carter
model and its modified version, which is the functional data model.
The models were evaluated using the out-sample forecast error
measures. Results indicate that the third-order functional data
model able to capture most of variation present in the actual data,
consequently outperforming the Lee-Carter model in forecasting
fertility rates among Chinese and Indian populations. There was a
noteworthy shift in maternal ages of the highest births to older
ages suggesting a trend towards delayed pregnancies among
women. It is predicted that the Malay total fertility rates will likely
fall to below the replacement level reaching 1.71 in 2040 whereas
Chinese and Indian total fertility rates will substantially decrease
to the lowest level in history below 1.0 which are 0.54 and 0.70
respectively.