I lived with a surgeon for 25 years. From the decisions Ginny made, I learned that doctors are better than economists at balancing the costs and benefits of delay.

Economists teach that time is money, but we never specify the exchange rate. If delay costs $x per day per person, the total cost scales with the number of people. In my lifetime, the most important lesson economists have learned is that in countries of all sizes–small ones like Singapore, medium-sized ones like South Korea, large ones like China and India–better policy can lift people out of poverty more quickly than we dared hope. Because a billion people still live in extreme poverty, each day of delay in taking full advantage of this lesson imposes a cost that is staggering.

The mantra that emerged at Intel was “disagree, then commit.” Economists disagree elegantly but endlessly because we use uncertainty as an excuse not to commit. Doctors learn to commit because they meet the people they serve and see firsthand how costly delay can be. The longer a seizure lasts, the harder it is to stop. There are several drugs that can help bring one to an end. When a patient is seizing, delay is so costly that doctors tend to administer a default without taking the time to collect all the information they would need to decide which would be best.

Ginny’s surgical practice involved clinical decisions about cancer. She also did research on cancer therapy, which led to a job at a pharmaceutical company. I observed several iterations of a scenario that, in the first instance, went like this:

Management: Ginny, could you look at our project on the pharmacological manipulation of circadian rhythm as a possible treatment for jet lag? We have been working on this for years and have invested millions. The team reports that one more study would confirm whether it works. We know this is outside of your realm of expertise, but could you tell us what you think?

Ginny, reporting back: Shut the project down. Don’t worry about what to say. The team understands.

Management: Oh no! Did you ask Communications about the right way to deliver bad news?

Ginny: If by “right” you mean without upsetting anyone, there is no right way. Bad news is upsetting.

The team has been focused on the science, which is exciting. But the potential revenue is smaller than they realized. A treatment for jet lag sounds great to us, but we are not representative of the population. Each year, relatively few people travel across many time zones.

I told the team as soon as this became clear, even though I knew they would hate giving up without learning whether the treatment works. It’s like the time I learned that a single mother’s tumor had metastasized and would soon kill her. I spoke to her right away and explained the new information as clearly as I could, without hiding behind the type of euphemism that Communications would suggest. She had important decisions to make.

She raged against the gods; against doctors too. Then we talked about whether it would be better for her children if she died at home or in a hospice.

When I heard in 2012 that the final choice for the president of the World Bank was between an outsider M.D. and two insider economists, I sided with the economists. What I did not see then, but do see now, is that the Bank had the same problem as the pharmaceutical company that Ginny joined. An early success generated lots of revenue. For years, it followed a strategy of “letting 100 flowers bloom” by spending more on research when new projects surfaced. Before Ginny arrived, it had reached the limit on research spending but had not yet developed the capacity to shut down projects that turned out to have only modest prospects. Because she had experience with clinical medicine and could look with fresh eyes, Ginny was better than the insiders at acting without delay, pulling the plug on even good projects, and freeing up resources for new ones with the potential to be great.

I now see that back in 2012, the Obama Administration made an inspired choice when it nominated the outsider M.D., Jim Yong Kim, to be the president of the Bank. This summer, I decided to join the Bank because I saw the cuts and restructuring of Jim’s first term and expected that he would be asked to stay on and complete the transformation of the Bank into the type of impatient organization that forces decisions, refuses to settle for modest success, and shuts things down without concern for the feelings of insiders. This will give it the chance to keep starting projects that are as unreasonably ambitious as the ones that turned out so well in Singapore, South Korea, China, and India. Some of the new ones, perhaps many, will disappoint and will in turn be stopped. As long as everyone commits to “failing fast,” and no one treats a shut-down as shameful or an insult to honor, failures cost little. What matters are the dramatic successes. It takes only a few to make a world of difference.

An impatient Bank will produce some bruised feelings for the people the Bank employs. These are of little consequence compared to the benefits that it can generate for the people the Bank serves.

Delay is costly. Impatience is a virtue.