cellsupp: Cell suppression with complementary suppression and a...

In rmoriedata: Integrated Datasets for the 'rmorie' Package

Cell suppression with complementary suppression and a recoverability audit

Description

Suppresses (sets to NA) every count below threshold, then, when retcomp = TRUE, hides further cells until no suppressed value can be solved exactly from the table's row and column totals, which a published table normally carries.

Usage

cellsupp(tbl, threshold = 5, retcomp = TRUE)

Arguments

tbl	A numeric matrix or 2-D table of counts. Will be coerced to matrix; row/column names are preserved.
threshold	Minimum count to remain unsuppressed. Default 5.
retcomp	Logical; if TRUE (default), add complementary suppressions until no hidden cell is recoverable from the row and column totals.

Details

Complements are added to a fixed point. A row or column holding exactly one hidden cell gives that cell away by subtraction, so every line with a hidden cell gets a second one; a complement placed for a row is a hidden cell in its column too, so the passes repeat until no line holds a lone hidden cell. That condition is necessary but not sufficient, so the result is then audited exactly: a hidden cell is recoverable when the linear system of row and column totals determines it (its indicator lies in the row space of the constraints over the hidden cells). Any recoverable cell receives another complement in its row, and the audit repeats. Complements are taken from positive cells, preferring one in a line that already holds a hidden cell (which creates no new lone cell), then the largest such cell, which leaves the widest range for the hidden values. A zero cell is never used as a complement: it would bound the hidden values from below at nothing.

The audit covers exact recovery from the margins. It does not compute the feasible interval of each hidden cell, which bounds from non-negativity can narrow; a table whose hidden values must stay inside a wide interval needs an interval audit (linear programming) on top.

Only finite numeric cells are eligible for suppression. NA cells in the input pass through unchanged and are treated as unpublished.

Value

A list with class "cellsupp":

suppressed

numeric matrix, suppressed cells set to NA.

primary_mask

logical matrix, TRUE for primary suppressions.

complementary_mask

logical matrix, TRUE for complementary suppressions (all FALSE when retcomp = FALSE).

recoverable_mask

logical matrix, TRUE for a hidden cell whose value the row and column totals determine exactly.

protected

logical, TRUE when no hidden cell is recoverable. Test this before publishing.

n_primary

integer.

n_complementary

integer.

n_recoverable

integer.

threshold

the threshold used.

Examples

tbl <- matrix(c(120, 3, 47, 88, 2, 99, 14, 51, 60),
  nrow = 3,
  dimnames = list(c("A", "B", "C"), c("X", "Y", "Z"))
)

res <- cellsupp(tbl, threshold = 5)
res$suppressed # NA where suppressed
res$protected # no hidden cell can be solved from the totals
res$n_primary # cells below threshold
res$n_complementary # extra cells hidden to protect them

# Without complements the small cells are hidden but recoverable.
bare <- cellsupp(tbl, threshold = 5, retcomp = FALSE)
bare$protected
bare$recoverable_mask

# Works on a 2-D table too; NA cells pass through untouched.
t2 <- as.table(matrix(c(2, 40, 30, 1), 2,
  dimnames = list(c("a", "b"), c("c", "d"))
))
cellsupp(t2, threshold = 5)$suppressed

rmoriedata documentation built on Nov. 12, 2026, 9:06 a.m.