Make a two-by-two table — make_two_by_two

Makes a two-by-two contingency table which takes the visual form:

Where A, B, C, and D are the distinct number of subjects satisfying the criteria of each 2x2 cell.

Only observations that have a Treatment value recorded are returned.

Usage

make_two_by_two_(
  dat,
  event_index,
  cell_index,
  treatment_var,
  treatment_refval,
  subjectid_var
)

dat: data.table. The analysis data set.
event_index: vector of integers that index the rows in dat that match the definition of an 'event'. Matching is done via the INDEX_ column in dat.
cell_index: A vector of integers referencing the rows of dat (as specified by the INDEX_ column in dat) that match the population to be analyzed. See the "Endpoint Events" vignette in ramnog for more information.
treatment_var: character. The name of the treatment variable in dat.
treatment_refval: character. The reference value of the treatment variable in dat.
subjectid_var: character. Name of the subject identifier variable in dat (default is "USUBJID").

A matrix