This research was carried out to appraise the influence of fertility and migration
on the age-sex population structure of Lagos State, Nigeria. Respondents were randomly
selected and given questionnaire to fill with regards to fertility and migration trends in the
study area. Using partial correlation and multiple regression analyses, we determined the
influence of migration and fertility on the age structure of the population. The combined
effects of the partial correlation of fertility and migration were 0.66 (males) and 0.79
(females). The regression analyses yielded influence of fertility of 9.6 and 11.7 for males
and females respectively, which far outstrips the influence of migration of 6.4 and 1.5 for
males and females respectively on the age-sex structure. Also, the base constant was –5.1
for females and –3.2 for males i.e. the minimum change in age of male and female
populations that would occur before the influence of fertility and migration become
noticeable. Finally, the socio-economic implications of the age-sex structure were
highlighted.