How should policymakers and providers make decisions when faced with a dearth of evidence? do you prefer a more cautious approach that does not approve procedures or drugs until evidence is available or a more aggressive approach that encourages experimentation and use of treatments that appear to be effective? what about medical care for children, who are generally excluded from clinical and research trials for ethical reasons? when, if ever, is it appropriate for insurers to cover or the government to pay for treatments that are not proven effective?