migest (version 2.0.3)

ffs_rates: Estimation of bilateral migrant flows from bilateral migrant stocks using rates approaches

Description

Estimates migrant transitions flows between two sequential migrant stock tables using approached based on rates.

Usage

ffs_rates(m1 = NULL, m2 = NULL, M = NULL, method = "dennett")

Value

Estimates migrant transitions flows based on migration rates.

When method = "dennett" migration are derived from the matrix supplied to m1. Dennett uses bilateral migrant stocks at beginning of period. Rates then multiplied by global migration flows supplied in M.

When method = "rogers-von-rabenau" a matrix of growth rates are derived from the changes in initial populations stock m1 to obtain m2; $$P^{t+1} = g P^{t}$$

and then multiplied by the corresponding populations at risk in m1. Can result in negative flows.

Arguments

m1

Matrix of migrant stock totals at time t. Rows in the matrix correspond to place of birth and columns to place of residence at time t

m2

Matrix of migrant stock totals at time t+1. Rows in the matrix correspond to place of birth and columns to place of residence at time t+1.

M

Numeric value for the global sum of migration flows, used for dennett approach.

method

Method to estimate flows. Can take values dennett or rogers-von-rabenau. See details section for more information. Uses dennett as default.

Author

Guy J. Abel

References

Dennett, A. (2015). Estimating an Annual Time Series of Global Migration Flows - An Alternative Methodology for Using Migrant Stock Data. Global Dynamics: Approaches from Complexity Science, 125–142. https://doi.org/10.1002/9781118937464.ch7

Rogers, A., & Von Rabenau, B. (1971). Estimation of interregional migration streams from place-of-birth-by-residence data. Demography, 8(2), 185–194.

See Also

ffs_demo, ffs_rates

Examples

s1 <- matrix(data = c(100, 10, 10, 0, 20, 55, 25, 10, 10, 40, 140, 65, 20, 25, 20, 200),
             nrow = 4, ncol = 4, byrow = TRUE)
s2 <- matrix(data = c(75, 25, 5, 15, 20, 45, 30, 15, 30, 40, 150, 35, 10, 50, 5, 200),
             nrow = 4, ncol = 4, byrow = TRUE)
r <- LETTERS[1:4]
dimnames(s1) <- dimnames(s2) <- list(pob = r, por = r)
s1; s2

# calculate total migration flows for dennett approach
n <- colSums(s2) - colSums(s1)

ffs_rates(m1 = s1, M =  sum(abs(n)), method = "dennett" )
ffs_rates(m1 = s1, m2 = s2, method = "rogers-von-rabenau" )