Asymmetric Information | Megan McArdle | Bloomberg’s Latest Crackdown: Prescription DrugsMcArdle is being way too generous. There is no possible way, mathematically, that zero legitimate patients will be harmed.
ERs will face stiff limits on prescribing pain medication.
Prescription drug abuse is growing, and it's getting expensive. New York's Mayor Bloomberg has announced a new initiative to crack down:
Under the new city policy, most public hospital patients will no longer be able to get more than three days’ worth of narcotic painkillers like Vicodin and Percocet. Long-acting painkillers, including OxyContin, a familiar remedy for chronic backache and arthritis, as well as Fentanyl patches and methadone, will not be dispensed at all. And lost, stolen, or destroyed prescriptions will not be refilled. [...]
The administration says that "There will be no chance that the patients who need pain relief will not get pain relief." I'm not so sure.
This is the essence of the No Free Lunch Theorem. You can not change your decision rule and guarantee that you will only decrease false positives without also increasing false negatives. There is simply no way to guarantee a priori that your policy will only makes the correct decisions regarding who should and who should not be given drugs.
This isn't a matter of politics or even of policy. It's scientifically impossible to that there is "no chance" this system doesn't increase false negatives — i.e. result in some people who should get drugs not getting them.