Among the indicators computed in the population submodel of IFs are the crude birth rate (CBR) and crude death rate (CDR).
Population growth rate (POPR) follows easily from crude death and birth rates.
Regional population (POP) is simply a sum across age cohorts.
For information and use elsewhere in the model, three computations of sub-portions of the population by age are made (POPLE15, POP15TO65, and POPGT65). [Note: each one of these is slightly misnamed.]
More recently the IFs model has recognized that the working life span is not uniformly from 15 to 65 across countries or time and has designated country/region specific parameters for age of work entry ( workageentry ) and retirement ( workaageretire ). These are used to compute POPPREWORK, POPWORKING, and POPRETIRED. They also allow the computation of a potential support ratio for the retired population (POTSUPRAT), which is the ratio of those of working population to those of retirement age.
Another useful indicator is the youth bulge (YTHBULGE), defined as the ratio of the population between ages 15-29 to that aged 15 and above. In general, a ratio of more than 0.4 and especially 0.5 suggests a particularly youthful society and may indicate potential for social instability.
Median age (POPMEDAGE) is another useful indicator and the age distribution (fagedst) can be used to determine that age at which there are equal numbers of people older and younger.
World population (WPOP) and world population growth rate (WPOPR) are simple functions across countries/regions.