Intertemporal preferences are difficult to measure. We estimate time preferences using a structural buffer stock consumption model and the Method of Simulated Moments. The model includes stochastic labor income, liquidity constraints, child and adult dependents, liquid and illiquid assets, revolving credit, retirement, and discount functions that allow short-run and long-run discount rates to differ. Data
Public-private partnerships (PPPs) cannot be justified because they free public funds. When PPPs are desirable because the private sector is more efficient, the contract that optimally trades demand risk, user-fee distortions and the opportunity cost of public funds is characterized by a minimum revenue guarantee and a cap on the firm’s revenues. Yet income guarantees