Population - IFs
|Model Documentation - IFs|
|Institution||Frederick S. Pardee Center for International Futures, University of Denver https://pardee.du.edu/ (Pardee Center), Colorado, USA, .|
The dominant population equation is a simple addition of births (BIRTHS) at the bottom of the cohort distribution, subtraction of deaths (DEATHS) from each population cohort, and advance of people to the next cohort over time. Although the output from IFs shows population in the standard 5-year age categories, the model maintains single-year categories internally to be consistent with its one-year time steps, thereby avoiding numerical diffusion of changes to the bottom of 5-year categories to higher age categories.
Births are most immediately a function of the total fertility rate (TFR), which in the longer term responds especially to education level of the adult population, infant mortality rates, and contraception usage rates. The model user has direct control over TFR with a multiplier and for low fertility countries with a parameter specifying long-term stabilization level for fertility.
Deaths are primarily a function of age-sex specific mortality rates computed within the IFs health model where they respond in the long run to adult education and also to GDP per capita and technology change, as well as mortality cause specific proximate drivers (e.g. indoor (solid fuel related) or urban air pollution). The model user has direct control over all deaths with a mortality multiplier and over those specific to a cause of health with an alternative mortality multiplier