| check_balance | Check covariate balance of the control and treated groups |
| create_dist_matrix | Create matrix of distances between strata |
| generate_constraints | Generate constraints to encourage covariate balance |
| generate_qs | Calculate desired number of controls per stratum |
| nh0506 | Homocysteine and smoking example data |
| nh0506_3groups | Homocysteine and smoking example data with multiple control groups |
| optimize_controls | Select control units that optimize covariate balance |
| stand | Standardize covariate vector for balance constraint |