# Estimation of bilateral migrant flows from bilateral migrant stocks using demographic accounting approaches Estimates migrant transitions flows between two sequential migrant stock tables. Replaces old `ffs`. ```r ffs_demo( stock_start = NULL, stock_end = NULL, births = NULL, deaths = NULL, seed = NULL, stayer_assumption = TRUE, match_global = "before-demo-adjust", match_birthplace_tot_method = "rescale", birth_method = "native", birth_non_negative = TRUE, death_method = "proportion", verbose = FALSE, return = "flow" ) ``` ## 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**. Previously had argument name `m1`. - `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. Previously had argument name `m2`. - `births`: Vector of the number of births between time **t** and **t**+1 in each region. Previously had argument name `b_por`. - `deaths`: Vector of the number of deaths between time **t** and **t**+1 in each region. Previously had argument name `d_por`. - `seed`: Matrix of auxiliary data. By default set to 1 for all origin-destination combinations. Previously had argument name `m`. - `stayer_assumption`: Logical value to indicate whether to use a quasi-independent or independent IPFP to estimate flows. By default uses quasi-independent, i.e. is set to `TRUE` and estimates the minimum migration. When set to `FALSE` estimates flows under the independent model as used as part of Azose and Raftery (2019). - `match_global`: Character string used to indicate whether to balance the change in stocks totals with the changes in births and deaths. Only applied when `match_birthplace_tot_method` is either `rescale` or `rescale-adjust-zero-fb`. By default uses `after-demo-adjust` rather than `before-demo-adjust` which I think minimises risk of negative values. - `match_birthplace_tot_method`: Character string passed to `method` argument in `match_birthplace_tot` to ensure place of birth margins in stock tables match. - `birth_method`: Character string passed to `method` argument in `birth_mat`. - `birth_non_negative`: Logical value passed to `non_negative` argument in `birth_mat`. - `death_method`: Character string passed to `method` argument in `death_mat`. - `verbose`: Logical value to show progress of the estimation procedure. By default `FALSE`. - `return`: Character string used to indicate whether to return the array of estimated flows when set to `flow` (default), array of demographic accounts when set to `account` or the demographic account, list of input settings and the origin-destination matrix when set to `classic` ## Returns Estimates migrant transitions flows between two sequential migrant stock tables using various methods. See the example section for possible variations on estimation methods. Detail of returned object varies depending on the setting used in the `return` argument. ## Examples ```r ## ## without births and deaths over period ## # data as in demographic research and science paper papers s1 <- matrix(data = c(1000, 100, 10, 0, 55, 555, 50, 5, 80, 40, 800, 40, 20, 25, 20, 200), nrow = 4, ncol = 4, byrow = TRUE) s2 <- matrix(data = c(950, 100, 60, 0, 80, 505, 75, 5, 90, 30, 800, 40, 40, 45, 0, 180), nrow = 4, ncol = 4, byrow = TRUE) b <- d <- rep(0, 4) r <- LETTERS[1:4] dimnames(s1) <- dimnames(s2) <- list(birth = r, dest = r) names(b) <- names(d) <- r addmargins(s1) addmargins(s2) b d # demographic research and science paper example e0 <- ffs_demo(stock_start = s1, stock_end = s2, births = b, deaths = d) e0 sum_od(e0) # international migration review paper example s1[,] <- c(100, 20, 10, 20, 10, 55, 40, 25, 10, 25, 140, 20, 0, 10, 65, 200) s2[,] <- c(70, 25, 10, 40, 30, 60, 55, 45, 10, 10, 140, 0, 10, 15, 50, 180) addmargins(s1) addmargins(s2) e1 <- ffs_demo(stock_start = s1, stock_end = s2, births = b, deaths = d) sum_od(e1) # international migration review supp. material example # distance matrix dd <- matrix(data = c(0, 5, 50, 500, 5, 0, 45, 495, 50, 45, 0, 450, 500, 495, 450, 0), nrow = 4, ncol = 4, byrow = TRUE) dimnames(dd) <- list(orig = r, dest = r) dd e2 <- ffs_demo(stock_start = s1, stock_end = s2, births = b, deaths = d, seed = dd) sum_od(e2) ## ## with births and deaths over period ## # demographic research paper example (with births and deaths) s1[,] <- c(1000, 55, 80, 20, 100, 555, 40, 25, 10, 50, 800, 20, 0, 5, 40, 200) s2[,] <- c(1060, 45, 70, 30, 60, 540, 75, 30, 10, 40, 770, 20, 10, 0, 70, 230) b[] <- c(80, 20, 40, 60) d[] <- c(70, 30, 50, 10) e3 <- ffs_demo(stock_start = s1, stock_end = s2, births = b, deaths = d, match_birthplace_tot_method = "open-dr") sum_od(e3) # makes more sense to use this method e4 <- ffs_demo(stock_start = s1, stock_end = s2, births = b, deaths = d, match_birthplace_tot_method = "open") sum_od(e4) # science paper supp. material example b[] <- c(80, 20, 60, 60) e5 <- ffs_demo(stock_start = s1, stock_end = s2, births = b, deaths = d) sum_od(e5) # international migration review supp. material example (with births and deaths) s1[,] <- c(100, 20, 10, 20, 10, 55, 40, 25, 10, 25, 140, 20, 0, 10, 65, 200) s2[,] <- c(75, 20, 30, 30, 25, 45, 40, 30, 5, 30, 150, 20, 0, 15, 60, 230) b[] <- c(10, 50, 25, 60) d[] <- c(30, 10, 40, 10) e6 <- ffs_demo(stock_start = s1, stock_end = s2, births = b, deaths = d) sum_od(e6) # scientific data 2019 paper s1[] <- c(100, 80, 30, 60, 10, 180, 10, 70, 10, 10, 140, 10, 0, 90, 40, 160) s2[] <- c(95, 75, 55, 35, 5, 225, 0, 25, 15, 5, 115, 25, 5, 55, 50, 215) b[] <- c(0, 0, 0, 0) d[] <- c(0, 0, 0, 0) e7 <- ffs_demo(stock_start = s1, stock_end = s2, births = b, deaths = d) sum_od(e7) ``` ## References Abel and Cohen (2019) Bilateral international migration flow estimates for 200 countries **Scientific Data** 6 (1), 1-13 Azose & Raftery (2019) Estimation of emigration, return migration, and transit migration between all pairs of countries **Proceedings of the National Academy of Sciences** 116 (1) 116-122 Abel, G. J. (2018). Estimates of Global Bilateral Migration Flows by Gender between 1960 and 2015. **International Migration Review** 52 (3), 809–852. Abel, G. J. and Sander, N. (2014). Quantifying Global International Migration Flows. **Science**, 343 (6178) 1520-1522 Abel, G. J. (2013). Estimating Global Migration Flow Tables Using Place of Birth. **Demographic Research** 28, (18) 505-546 ## See Also `ffs_diff`, `ffs_rates` ## Author(s) Guy J. Abel

ffs_demo function