Which population estimation method uses the population at the time of the last Census divided into five-year age groups and gender, applies a death rate to each group, and creates new groups based on birth rates and net migration?

• A. Linear extrapolation
• B. Cohort Survival
• C. Arithmetic growth
• D. Geometric growth

Answer: (B)

This method is the cohort component approach. It starts from the population in the last Census broken into five-year age groups and by sex. For each age–sex group, it applies age-specific death rates to estimate how many will survive to the next period. Births are then used to form the new youngest group, and net migration is incorporated to adjust the size of each group. After accounting for deaths, births, and migration, the groups are advanced by five years to create the updated population distribution. This approach explicitly models the demographic processes—births, deaths, and migration—by age and sex, which is why it’s the best fit for this description. Linear extrapolation simply extends past trends without those components, while arithmetic and geometric growth are generic growth models that don’t separately account for age-specific survival and migration.