as_matchit: Convert couplr Result to matchit Object

In couplr: Optimal Pairing and Matching via Linear Assignment

Convert couplr Result to matchit Object

Description

Constructs a matchit-class S3 object from a couplr result, enabling use with any function that accepts MatchIt objects (e.g., cobalt, marginaleffects).

Usage

as_matchit(
  result,
  left,
  right,
  formula = NULL,
  left_id = "id",
  right_id = "id",
  estimand = NULL,
  ...
)

Arguments

result	A couplr result object (matching_result, full_matching_result, cem_result, or subclass_result)
left	Data frame of left (treated) units
right	Data frame of right (control) units
formula	Optional formula used for matching. If not provided, a default formula is constructed from result$info$vars.
left_id	Name of ID column in left (default: "id")
right_id	Name of ID column in right (default: "id")
estimand	Target estimand stamped on the matchit object: one of "ATT", "ATC" or "ATE". NULL (default) reads it from the design, which every couplr front door records as info$estimand. MatchIt and marginaleffects read this field to pick the target population and the weighting of the effect estimate, so give it explicitly whenever the design does not determine it – in particular when left holds the controls, which makes the design's left-focal weighting an ATC.
...	Additional arguments (ignored)

Value

An S3 object of class "matchit" with fields:

match.matrix

Match matrix (treated x controls)

treat

Named treatment vector (1/0)

weights

Matching weights

X

Covariate matrix

call

Original call

info

Metadata from couplr

Examples

## Not run: 
left <- data.frame(id = 1:5, age = c(25, 35, 45, 55, 65))
right <- data.frame(id = 6:15, age = runif(10, 20, 70))
result <- match_couples(left, right, vars = "age")
mi <- as_matchit(result, left, right)
# Now use with cobalt:
cobalt::bal.tab(mi)

## End(Not run)

couplr documentation built on Sept. 17, 2026, 1:08 a.m.