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Apply IQR-Based Top and Bottom Coding to LIS/LWS Variables

apply_iqr_top_bottom_coding.Rd

This function performs top and/or bottom coding on a specified variable across a list of LIS/LWS datasets. It applies an interquartile range (IQR)-based rule on the log() transformation of the variable. Optionally, weights can be supplied, and the transformation can be one- or two-sided.

Usage

apply_iqr_top_bottom_coding(
  data_list,
  var_name,
  wgt_name = NULL,
  times = 3,
  one_sided = NULL,
  type = c("type_4", "type_2")
)

Arguments

data_list

A named list of data frames, from LIS or LWS microdata.

var_name

Character string. Name of the variable to code (e.g., "dhi").

wgt_name

Optional character string. Name of the weight variable to use in computing weighted percentiles.

times

Numeric. The IQR multiplier for determining bounds (default is 3).

one_sided

Character. Set to "top", "bottom", or NULL for two-sided coding.

type

Character. Type of quantile estimator to use (default is "type_4").

Value

A list of data frames with the same structure as data_list, where var_name has been adjusted by bounding extreme values according to an IQR rule.

Details

The function:

  • Transforms the variable to log() scale (logarithmic transformation).

  • Replaces invalid log-values (e.g. from log(0) or negatives) with zero.

  • Computes the IQR (interquartile range) on the log-transformed variable using weighted percentiles.

  • Caps values beyond \([Q1 - times * IQR, Q3 + times * IQR]\) on the original scale using exp().

Regarding LWS datasets:

  • Datasets with multiple imputations (via inum) are detected automatically.

  • Top and bottom coding is applied within each imputation group in such datasets.

  • Datasets without inum, or with only a single imputation, are processed normally.

A warning is issued if the variable level (e.g. household vs individual) seems inconsistent with the dataset structure.

Examples

if (FALSE) { # \dontrun{ 
# Import data, ideally at the level of the variable of interest.
data_hhd <- lissyrtools::lissyuse("au", vars = c("dhi"), from = 2016)

# Default case, where top and bottom coding is performed simultaneously
data_hhd[1]  %>%
 purrr::map(~ .x[!is.na(.x$dhi), ]) %>%
 purrr::map(~ .x %>% mutate(new_wgt = nhhmem * hwgt)) %>%
 apply_iqr_top_bottom_coding("dhi", "hwgt", times = 3) %>% 
 run_weighted_mean("dhi", "new_wgt")

# Example with the use or arguments `one_sided` = {"top", "bottom"} and `type`
data_hhd[1]  %>%
 purrr::map(~ .x[!is.na(.x$dhi), ]) %>%
 purrr::map(~ .x %>% mutate(new_wgt = nhhmem * hwgt)) %>%
 apply_iqr_top_bottom_coding("dhi", "hwgt", one_sided = "top", type = "type_2") %>% 
 run_weighted_mean("dhi", "new_wgt")

# Load individual-level datasets by selecting individual-level variables, if the target variable is at the individual level (e.g., "pilabour")
data_ind <- lissyrtools::lissyuse("au", vars = c("pilabour", "emp"), from = 2016)

data_ind[1]  %>%
 purrr::map(~ .x[!is.na(.x$pilabour), ] %>% filter(emp ==1)) %>%
 apply_iqr_top_bottom_coding("pilabour", "ppopwgt") %>% 
 run_weighted_percentiles("pilabour", "ppopwgt", probs = seq(0.1, 0.9,0.1))
} # }