sp_open0: Simple Projection Model Based on Crude Demographic Rates and...
In gjabel/demoproj: Demographic Projection Models

Description Usage Arguments Value Examples

A simple projection model based on crude fertility, survival and emigration rates and immigration counts,

N_{t+1} = ≤ft( N_t + \frac{I_{t,t+1}}{2} \right) \times (1 + b_{t,t+1} - d_{t,t+1} - e_{t,t+1}) + \frac{I_{t,t+1}}{2}

sp_open0(n = NULL, N0 = NULL, b = NULL, d = NULL, e = NULL,
  I = NULL)

sp_open(n = NULL, N0 = NULL, b = NULL, d = NULL, e = NULL, I = NULL)

n

Numeric value for the number of projection periods to run the model.

N0

Numeric value for the initial total population size.

b, d, e, I

Numeric value for the crude birth, death and emigration rate and immigration count in each projection period.

If sp_open0 is used a single value is required.

If sp_open is used a vector of period specific rates (and immigration counts) is required. If a single rate values (and immigration count) are passed to sp_open a vector based on constant assumptions in all future rates (and immigration counts) will be constructed.

A vector of length n + 1 containing the initial total population size (N0) and the projected total population sizes given b, d, e and I.

sp_open0 produces population projections based strictly on constant future rates and counts.

sp_open produces population projections based non-constant future rates and counts.

# constant future assumptions
sp_open0(n = 20, N0 = 100, b = 0.04, d = 0.02, e = 0.01, I = 4)

# non-constant future assumptions
bb <- rnorm(n = 20, mean = 0.04, sd = 0.001)
ee <- rnorm(n = 20, mean = 0.01, sd = 0.001)
sp_open(n = 20, N0 = 100, b = bb, d = 0.02, e = ee, I = 4)