FindDisclosiveCells {SSBtools}

Find directly disclosive cells

Description

Function for determining which cells in a frequency table can lead to direct disclosure of an identifiable individual, assuming an attacker has the background knowledge to place themselves (or a coalition) in the table.

Usage

FindDisclosiveCells(
  data,
  freq,
  crossTable,
  primaryDims = names(crossTable),
  unknowns = rep(NA, length(primaryDims)),
  total = rep("Total", length(primaryDims)),
  unknown.threshold = 0,
  coalition = 1,
  suppressSmallCells = FALSE,
  ...
)

Arguments

data

the data set

freq

vector containing frequencies

crossTable

cross table of key variables produced by ModelMatrix in parent function

primaryDims

dimensions to be considered for direct disclosure.

unknowns

vector of unknown values for each of the primary dimensions. If a primary dimension does not contain unknown values, NA should be passed.

total

string name for marginal values

unknown.threshold

numeric for specifying a percentage for calculating safety of cells. A cell is "safe" in a row if the number of unknowns exceeds unknown.threshold percent of the row total.

coalition

maximum number of units in a possible coalition, default 1

suppressSmallCells

logical variable which determines whether small cells (<= coalition) or large cells should be suppressed. Default FALSE.

...

parameters from main suppression method

Details

This function does not work on data containing hierarchical variables.

Value

list with two named elements, the first ($primary) being a logical vector marking directly disclosive cells, the second ($numExtra) a data.frame containing information regarding the dimensions in which the cells are directly disclosive.

Examples

extable <- data.frame(v1 = rep(c('a', 'b', 'c'), times = 4),
            v2 = c('i','i', 'i','h','h','h','i','i','i','h','h','h'),
            v3 = c('y', 'y', 'y', 'y', 'y', 'y','z','z', 'z', 'z', 'z', 'z'),
            freq = c(0,0,5,0,2,3,1,0,3,1,1,2))
ex_freq <- c(18,10,8,9,5,4,9,5,4,2,0,2,1,0,1,1,0,1,3,2,1,3,2,1,0,0,0,13,8,5,
             5,3,2,8,5,3)
cross <- ModelMatrix(extable,
                     dimVar = 1:3,
                     crossTable = TRUE)$crossTable

FindDisclosiveCells(extable, ex_freq, cross)