Calculates detailed within-category segregation scores for M and H
Source:R/mutual.R
      mutual_within.RdCalculates the segregation between group and unit
within each category defined by within.
Usage
mutual_within(
  data,
  group,
  unit,
  within,
  weight = NULL,
  se = FALSE,
  CI = 0.95,
  n_bootstrap = 100,
  base = exp(1),
  wide = FALSE
)Arguments
- data
- A data frame. 
- group
- A categorical variable or a vector of variables contained in - data. Defines the first dimension over which segregation is computed.
- unit
- A categorical variable or a vector of variables contained in - data. Defines the second dimension over which segregation is computed.
- within
- A categorical variable or a vector of variables contained in - datathat defines the within-segregation categories.
- weight
- Numeric. (Default - NULL)
- se
- If - TRUE, the segregation estimates are bootstrapped to provide standard errors and to apply bias correction. The bias that is reported has already been applied to the estimates (i.e. the reported estimates are "debiased") (Default- FALSE)
- CI
- If - se = TRUE, compute the confidence (CI*100) in addition to the bootstrap standard error. This is based on percentiles of the bootstrap distribution, and a valid interpretation relies on a larger number of bootstrap iterations. (Default- 0.95)
- n_bootstrap
- Number of bootstrap iterations. (Default - 100)
- base
- Base of the logarithm that is used in the calculation. Defaults to the natural logarithm. 
- wide
- Returns a wide dataframe instead of a long dataframe. (Default - FALSE)
Value
Returns a data.table with four rows for each category defined by within.
  The column est contains four statistics that
  are provided for each unit:
  M is the within-category M, and p is the proportion of the category.
  Multiplying M and p gives the contribution of each within-category
  towards the total M.
  H is the within-category H, and ent_ratio provides the entropy ratio,
  defined as EW/E, where EW is the within-category entropy,
  and E is the overall entropy.
  Multiplying H, p, and ent_ratio gives the contribution of each within-category
  towards the total H.
  If se is set to TRUE, an additional column se contains
  the associated bootstrapped standard errors, an additional column CI contains
  the estimate confidence interval as a list column, an additional column bias contains
  the estimated bias, and the column est contains the bias-corrected estimates.
  If wide is set to TRUE, returns instead a wide dataframe, with one
  row for each within category, and the associated statistics in separate columns.
References
Henri Theil. 1971. Principles of Econometrics. New York: Wiley.
Ricardo Mora and Javier Ruiz-Castillo. 2011. "Entropy-based Segregation Indices". Sociological Methodology 41(1): 159–194.
Examples
if (FALSE) { # \dontrun{
(within <- mutual_within(schools00, "race", "school",
    within = "state",
    weight = "n", wide = TRUE
))
# the M for state "A" is .409
# manual calculation
schools_A <- schools00[schools00$state == "A", ]
mutual_total(schools_A, "race", "school", weight = "n") # M => .409
# to recover the within M and H from the output, multiply
# p * M and p * ent_ratio * H, respectively
sum(within$p * within$M) # => .326
sum(within$p * within$ent_ratio * within$H) # => .321
# compare with:
mutual_total(schools00, "race", "school", within = "state", weight = "n")
} # }