library("matchatr")
two_phase(phase1 = "stratum", phase2 = "in_phase2")<matchatr_design>
Type: Two-phase
Phase 1: stratum
Phase 2: in_phase2
Weights: design (two-phase)Two-phase sampling design
Description
Declares a two-phase (double) sampling design: phase-1 variables are measured on the whole cohort and used to stratify a phase-2 subsample on which the expensive covariate is then measured. The analysis weights phase-2 records by the inverse of their phase-2 selection probability (survey / calibration estimators).
Usage
two_phase(phase1, phase2)
Arguments
phase1
|
A non-empty character vector naming the phase-1 stratification column(s) measured on the full cohort. |
phase2
|
A single character string naming the 0/1 (or logical) column flagging phase-2 selection. |
Value
A matchatr_design object of type “two_phase” carrying the phase-1 strata and phase-2 selection columns.
See Also
matcha()
Other design constructors: case_cohort(), counter_matched(), matched_cc(), nested_cc(), unmatched_cc()