1 Introduction  
1.1 Related Literature  
2 Motivation and Description of Method  
2.1 Matching Algorithms  
3 Asymptotic Theory  
3.1 Constant Sampling and Assignment Propensities  
3.2 Varying Sampling and Assignment Propensities  
4 Optimal Stratified Designs  
4.1 Budget-Constrained Sampling Problem  
4.2 Globally Optimal Stratification  
4.3 Finite Sample Optimality  
5 Design with a Pilot Experiment  
5.1 Feasible Optimal Stratification  
5.2 Estimating Stratification Variables  
6 Inference Methods  
7 Empirical Results  
8 Recommendations for Practice