print.md
In MatchIt: Nonparametric Preprocessing for Parametric Causal Inference

print.matchit: printed output is stable

Code
  print(matchit(f_pr, data = lalonde))
Output
  A `matchit` object
   - method: 1:1 nearest neighbor matching without replacement
   - distance: Propensity score
               - estimated with logistic regression
   - number of obs.: 614 (original), 370 (matched)
   - target estimand: ATT
   - covariates: age, educ, race, re74

Code
  print(matchit(f_pr, data = lalonde, method = NULL))
Output
  A `matchit` object
   - method: None (no matching)
   - distance: Propensity score
               - estimated with logistic regression
   - number of obs.: 614 (original)
   - target estimand: ATT
   - covariates: age, educ, race, re74

Code
  print(matchit(f_pr, data = lalonde, mahvars = ~ age + educ, caliper = c(0.1,
    age = 2), discard = "control", replace = TRUE, ratio = 2))
Output
  A `matchit` object
   - method: 2:1 nearest neighbor matching with replacement
   - distance: Mahalanobis [matching]
               Propensity score [caliper, common support]
               - estimated with logistic regression
   - caliper: <distance> (0.028), age (18.316)
   - common support: control units dropped
   - number of obs.: 614 (original), 303 (matched)
   - target estimand: ATT
   - covariates: age, educ, race, re74

Code
  print(matchit(treat ~ race + married, data = lalonde, method = "exact"))
Output
  A `matchit` object
   - method: Exact matching
   - number of obs.: 614 (original), 614 (matched)
   - target estimand: ATT
   - covariates: race, married

Code
  print(matchit(f_pr, data = lalonde, method = "subclass", subclass = 4))
Output
  A `matchit` object
   - method: Subclassification (4 subclasses)
   - distance: Propensity score
               - estimated with logistic regression
   - number of obs.: 614 (original), 614 (matched)
   - target estimand: ATT
   - covariates: age, educ, race, re74

Code
  print(matchit(f_pr, data = lalonde, method = "cardinality"))
Output
  A `matchit` object
   - method: Cardinality matching
   - number of obs.: 614 (original), 236 (matched)
   - target estimand: ATT
   - covariates: age, educ, race, re74

Code
  print(matchit(f_pr, data = lalonde, distance = "robust_mahalanobis"))
Output
  A `matchit` object
   - method: 1:1 nearest neighbor matching without replacement
   - distance: Robust Mahalanobis
   - number of obs.: 614 (original), 370 (matched)
   - target estimand: ATT
   - covariates: age, educ, race, re74

Code
  print(matchit(f_pr, data = lalonde, s.weights = rep(c(1, 2), length.out = nrow(
    lalonde))))
Output
  A `matchit` object
   - method: 1:1 nearest neighbor matching without replacement
   - distance: Propensity score
               - estimated with logistic regression
               - sampling weights included in estimation
   - number of obs.: 614 (original), 370 (matched)
   - sampling weights: present
   - target estimand: ATT
   - covariates: age, educ, race, re74