Extract the Final Cohort

Returns the dataset remaining after all exclusion criteria have been applied. When arms are defined via stratify(), the result is either a single combined data.table or a named list of per-arm data.table objects. Data mode only.

Usage

cohort(.flow, split = FALSE, arm = NULL)

Arguments

.flow

A selecta object created in data mode (data supplied to enroll()).

split

Logical. If TRUE and arms are defined, return a named list of data.tables (one per arm). Default FALSE returns a single combined data.table.

arm

Character. Name of a specific arm to extract. If supplied, returns only that arm's data.table.

Value

A data.table containing the participants remaining after all exclusion criteria. When split = TRUE, a named list of data.tables (one per arm). When arm is specified, a single-arm data.table.

Details

cohort() replays the exclusion criteria of a data-mode flow against the original dataset and returns the rows that survive to the end, so the analyst can pass the exact analyzed population to downstream modeling. It requires a flow created by supplying data to enroll(); manual-mode flows carry only counts and therefore raise an error. For an unsplit flow the result is a single data.table; after stratify() or allocate(), split = TRUE returns one table per arm and arm extracts a single named arm. To inspect the cohort at every intermediate step rather than only the end, use cohorts().

See also

cohorts for stage-by-stage snapshots, enroll for initializing a data-mode flow

Other cohort extraction functions: cohorts()

Examples

flow <- enroll(selectaex2, id = "patient_id") |>
  exclude("Ineligible", criterion = eligible == FALSE) |>
  endpoint("Final")

final <- cohort(flow)
nrow(final)
#> [1] 1549