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Document and apply a population flag

Source: R/population.R
lg_population.Rd

Population flags (SAFFL, ITTFL, PPROTFL, and custom flags) are first-class objects in lineager. Every flag must carry its inclusion criteria, exclusion criteria, and plain-English definition : the information needed to reconstruct the Reviewer's Guide population section automatically.

Usage

lg_population(
  data,
  flag_var,
  label,
  definition,
  incl_criteria,
  excl_criteria = NULL,
  included_value = "Y"
)

Arguments

data

An lg_df containing the flag variable.

flag_var

Character. The flag variable name (e.g. "SAFFL").

label

Character. Human label (e.g. "Safety Analysis Flag").

definition

Character. Plain-English definition for regulatory reviewers (e.g. "All randomised subjects who received at least one dose of study medication").

incl_criteria

Character vector of inclusion criteria as R expressions or plain English. At least one required.

excl_criteria

Character vector of explicit exclusion criteria. NULL if there are none beyond failing inclusion.

included_value

The value of flag_var that denotes inclusion. Defaults to "Y" (the CDISC convention), but lineager is general-purpose : if your flag is a logical column, pass included_value = TRUE; for any other custom coding, pass the actual included-value directly. Using the wrong value here silently produces incorrect included/excluded counts (e.g. a logical TRUE/FALSE flag compared against "Y" will count every row as excluded).

Value

data, invisibly (for pipe use).

Details

The flag variable must already exist in data. lg_population() documents it; it does not compute it. Compute the flag first with lg_derive(), then call lg_population() to register its definition.

See also

lg_filter(), lg_disposition(), lg_report()

Examples

lg_start()
#> lineager: session started
adsl <- lg_tag(
  data.frame(
    USUBJID = c("01", "02", "03"),
    RANDFL = c("Y", "N", "Y"), EXOCCUR = c("Y", "N", "Y"),
    SAFFL = c("Y", "N", "Y")
  ),
  dataset_id = "ADSL"
)
#> lineager: tagged 'ADSL' — 3 rows, 4 cols

lg_population(
  adsl,
  flag_var = "SAFFL",
  label = "Safety Analysis Flag",
  definition = "All randomised subjects who received at least one dose",
  incl_criteria = c("RANDFL == 'Y'", "EXOCCUR == 'Y'"),
  excl_criteria = "No study drug administered (EXOCCUR != 'Y')"
)
#> lineager: population 'SAFFL' (Safety Analysis Flag) — 2 included, 1 excluded