Matched case-control design

Description

Declares an individually or frequency matched case-control sample: each case is matched to one or more controls sharing the values of the matching variable(s). The design-faithful analysis is conditional logistic regression (conditional maximum likelihood), which conditions on the matched-set totals and so removes the matching-variable nuisance parameters; fitting matched-set indicators by ordinary logistic regression biases the odds ratio and is never used.

Usage

matched_cc(strata, ratio = NULL)

Arguments

strata	A non-empty character vector naming the column(s) that identify the matched sets (e.g. “set”, or c(“age_grp”, “sex”) for frequency matching).
ratio	NULL or a single whole number >= 1. The number of controls matched per case (m:1). Optional metadata; the conditional likelihood does not require a fixed ratio.

Value

A matchatr_design object of type “matched_cc” carrying the strata and ratio.

See Also

unmatched_cc(), nested_cc(), matcha()

Other design constructors: case_cohort(), counter_matched(), nested_cc(), two_phase(), unmatched_cc()

Examples

library("matchatr")

matched_cc(strata = "set")

<matchatr_design>
 Type:       Matched case-control
 Strata:     set
 Weights:    none

matched_cc(strata = c("age_grp", "sex"), ratio = 2)

<matchatr_design>
 Type:       Matched case-control
 Strata:     age_grp, sex
 Ratio:      2:1
 Weights:    none