Reader Sushil B. has the following comments on the Boston water crisis (see here).
As some of you may have heard, the city of Boston and surrounding suburbs is living under a "boil-water" order because of a break in the main water line from the Quabbin and Wachusett Reservoirs. This happened on Saturday and affects about 2 million people, or 700,000 households. In the meantime old reservoirs including ponds in and around the city are being tapped. Because of these sources, the powers that be are saying the water needs to be boiled before drinking or used in cooking.
What is the probability of falling sick if you don't boil the water? Is this just a case of much ado about nothing, or local governments creating a state of fear just to show people they are in control? Like Rahm Emanuel said, a good politician should never let “a serious crisis go to waste.”
The Boston Globe article stated that "The water is being heavily chlorinated to kill bacteria, but the Massachusetts Water Resources Authority said people shouldn’t drink it because no test results are back yet on bacteria levels."
Using the framework from Chapter 4, we should think about the incentives facing the Mass. Water Resources Authority.
A false positive error (people asked to throw out water when water is clean) means people stop drinking tap water temporarily, perhaps switching to bottled water, and the officials claim victory when no one falls sick, and businesses that produce bottled water experience a jump in sales. It is also very difficult to prove a "false positive" when people have stopped drinking the water. So this type of error is easy to hide behind.
A false negative error (people told it's safe to drink water when water is polluted) becomes apparent when someone falls sick as a result of drinking the water -- notice that it would be impossible to know if such a person is affected by bacteria from the pond water or bacteria from the main water line but no matter, any sickness will be blamed on the pond water. We think the risk is low but if it happens, the false negative error creates a public relations nightmare.
I think this goes a long way to explaining why government officials behave the way they do. This applies also to the FDA and CDC in terms of foodborne diseases (a subject of Chapter 2), and to the NTSB in terms of car recalls. They tend to be overly conservative. In the case of food or product recalls, being overly conservative leads to massive economic losses and waste as food or products are thrown out, almost all of them good.
What do you think? What if the risk is only 1 sick out of 1 million? Useful precaution or fear-mongering?