The study looks at how to set interest rates when they can't go below zero. It suggests that when rates are stuck at zero, it's best to lower them quickly when the economy is in trouble. This helps prevent future problems caused by people expecting rates to stay low. The study found that in the US, this strategy is important and can help reduce economic losses. However, having rates stuck at zero happens often and leads to big losses. Even though aiming for some inflation can help, it might not be as good as aiming for zero inflation. Making a commitment to a certain policy can greatly improve the situation when rates are stuck at zero.