migest (version 2.0.3)

index_distance: Summary indices of migration distance

Description

Summary indices of migration distance

Usage

index_distance(
  m = NULL,
  d = NULL,
  orig_col = "orig",
  dest_col = "dest",
  flow_col = "flow",
  dist_col = "dist",
  long = TRUE
)

Value

A tibble with 3 summary measures where

mean

Mean migration distance from Bell et. al. (2002) - not discussed in text but given in Table 6

median

Mean migration distance from Bell et. al. (2002)

decay

Distance decay parameter obtained from a Poisson regression model (flow ~ orig + dest + log(dist))

Arguments

m

A matrix or data frame of origin-destination flows. For matrix the first and second dimensions correspond to origin and destination respectively. For a data frame ensure the correct column names are passed to orig_col, dest_col and flow_col.

d

A matrix or data frame of origin-destination distances. For matrix the first and second dimensions correspond to origin and destination respectively. For a data frame ensure the correct column names are passed to orig_col, dest_col and dist_col. Region names should match those in m.

orig_col

Character string of the origin column name (when m is a data frame rather than a matrix)

dest_col

Character string of the destination column name (when m is a data frame rather than a matrix)

flow_col

Character string of the flow column name (when m is a data frame rather than a matrix)

dist_col

Character string of the distance column name (when dist is a data frame rather than a matrix)

long

Logical to return a long data frame with index values all in one column

Examples

# single year
index_distance(
  m = subset(korea_reg, year == 2020), 
  d = korea_dist
)

library(dplyr)
library(tidyr)
library(purrr)
# multiple years
korea_reg %>%
  nest(m = c(orig, dest, flow)) %>%
  mutate(d = list(korea_dist)) %>%
  mutate(i = map2(.x = m, .y = d, 
                  .f = ~index_distance(m = .x, d = .y, long = FALSE))) %>%
  select(-m, -d) %>%
  unnest(i)