migest (version 2.0.4)

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(stock_start = NULL, stock_end = 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 stock_start. 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 stock_start to obtain stock_end; $$P^{t+1} = g P^{t}$$

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

Arguments

stock_start

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

stock_end

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