Convert a long case-control event log to wide case-1-control format

Reshapes a long case-(k-)control dataset – one row per case and per control, with a 0/1 case indicator – into a wide case-1-control table with one row per case. For each covariate the event value (<cov>_ev), the matched control value (<cov>_nv) and their difference (d_<cov>, event minus control) are emitted, ready for the gam backend of rem().

Usage

widen_case_control(
  data,
  case = NULL,
  stratum = NULL,
  covariates = NULL,
  control_index = 1L,
  keep_ids = TRUE
)

Arguments

data: A long case-control data.frame.
case: Optional name of the 0/1 event-indicator column. If NULL (default), it is auto-detected from the package's event column (as produced by sample_non_events()) or eventnet's IS_OBSERVED, preferring event when both are present.
stratum: Optional name of the column grouping each case with its controls. When NULL, the stratum is derived as cumsum(case == 1) (assuming each case is immediately followed by its controls).
covariates: Character vector of covariate columns to widen. When NULL, all numeric columns are used except the case indicator, the stratum, and the standard eventnet bookkeeping columns (EVENT, INTEGER_TIME, TIME_POINT, TIME_UNIT, EVENT_INTERVAL).
control_index: Which control within each stratum to pair with the case (default the first). Lets a case-k-control log be reduced to case-1-control.
keep_ids: Logical; when TRUE (default) the sender/receiver identifier columns present in data are carried into the output as sender_ev / receiver_ev (the observed event) and sender_nv / receiver_nv (the matched control), so the dyads behind each case-control pair remain recoverable (and become available to re() grouping terms in rem()). Set to FALSE to emit only the widened covariate columns.

Value

A data.frame with one row per case: a stratum column, the sender/receiver identifiers (sender_ev/receiver_ev/sender_nv/ receiver_nv, when present in data and keep_ids = TRUE) and, for each covariate, <cov>_ev, <cov>_nv and d_<cov>. Strata without exactly one case or without the requested control are dropped (with a message).

Details

This is the preprocessing companion to rem() for eventnet-style output, where a case row is followed by its controls and the stratum id is left blank on control rows.

Examples

set.seed(1)
long <- data.frame(
  IS_OBSERVED = rep(c(1, 0, 0), 4),
  x = rnorm(12), y = rnorm(12))
widen_case_control(long, control_index = 1)
#>   stratum       x_ev      x_nv        d_x        y_ev        y_nv         d_y
#> 1       1 -0.6264538 0.1836433 -0.8100971 -0.62124058 -2.21469989  1.59345931
#> 2       2  1.5952808 0.3295078  1.2657730 -0.04493361 -0.01619026 -0.02874335
#> 3       3  0.4874291 0.7383247 -0.2508957  0.82122120  0.59390132  0.22731987
#> 4       4 -0.3053884 1.5117812 -1.8171696  0.78213630  0.07456498  0.70757132