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project: Geometric population projection

Source: R/project.R
project.Rd

Geometric population projection is a forecasting method assuming a constant percentage growth rate over time.

Usage

project(pop1, pop2, from = 2010, to = 2022, x = 2025)

Arguments

pop1

a vector of the initial values.

pop2

a vector of the ending values.

from

initial year or data point.

to

ending year or data point.

x

the year for which the extrapolation is to be made.

Value

This function returns a vector containing the extrapolated values.

Details

This function estimate values for a given year (x) based on growth rates calculated by geometric interpolation between from and to.

References

Laurenti, R., Mello Jorge, M.H.P., Lebrão, M.L., Gotlieb, S.L.D. (2005). Estatísticas de Saúde. 2nd edition. São Paulo: EPU. ISBN: 9788512408309.

Examples

## Example 1
project(100, 200, from=2010, to=2020, x=2025)
#> [1] 283

## Example 2
pop1 <- c(2126148L, 775746L, 884602L, 957100L, 911673L, 812483L, 747361L, 688740L,
          614103L, 501228L, 386337L, 274949L, 216546L)
pop2 <- c(1787296L, 648467L, 752059L, 783322L, 808350L, 881275L, 892896L, 771218L,
          713233L, 649157L, 581323L, 472760L, 356725L)
project(pop1, pop2, from=2010, to=2022, x=2025)
#>  [1] 1711383  620055  722151  745051  784404  899365  933509  793337  740421
#> [10]  692514  643843  541362  404138