We defined a “luck event” as one that meets three tests: First, you didn’t cause it; second, it has a significant potential consequence, good or bad; and third, it has an element of surprise, some aspect of the event is unpredictable before it happens. Using this definition, the evidence showed a lot of luck in the history of these companies. But— and this is the crucial point—we also found comparable amounts of luck in the control set of comparison cases we studied! The big winners did not generally get more good luck, less bad luck, bigger spikes of luck, or better-timed luck than their comparisons. What the best achieved, instead, was a higher return on luck. Hansen and I learned that the question is not whether you’ll get luck along the way—you certainly will get luck, both good luck and bad. The critical question is what you do with the luck that you get. I’ve come to believe that about 50 percent of great leadership is what you do with the unexpected.

I’d like to close this chapter with an essential caveat about persistence from Built to Last. Of all the paragraphs I’ve authored or co-authored in thirty years, this is one of the most essential for entrepreneurs and leaders of early-stage ventures, reproduced here as a reminder to keep firmly in mind as you build your company:

The builders of visionary companies were highly persistent, living to the motto: Never, never, never give up. But what to persist with? The company. Be prepared to kill, revise, or evolve an idea . . . but never give up on the company. If you equate the success of your company with the success of a specific idea—as many businesspeople do—then you’re more likely to give up on the company if that idea fails; and if that idea happens to succeed, you’re more likely to have an emotional love affair with that idea and stick with it too long, when the company should be moving vigorously on to other things. But if you see the ultimate creation as the company, not the execution of a specific idea . . . then you can persist beyond any specific idea—good or bad— and move toward becoming an enduring great institution.

(Again, to review from the previous chapter, a “luck event” meets three tests: First, you didn’t cause it; second, it has a significant potential consequence, good or bad; and third, it has an element of surprise, some aspect of the event is unpredictable before it happens.) Any framework that didn’t account for unpredictable and unforeseen events would be incomplete, and I couldn’t be intellectually satisfied until we wrestled with the question of luck. The concept of return on luck accounts for the undeniable fact that luck happens (a lot) yet captures the essential truth that luck itself cannot cause greatness. Catastrophic bad luck can kill a potentially great company, but good luck cannot make a company great. Luck doesn’t build great companies that last; people do.

But there’s also a hopeful story to tell. Companies can sustain greatness for decades, even if only a few do so. What this means is that you never get to the “end” of The Map. You’re never done with the journey. You’re never done with the need for disciplined people who engage in disciplined thought and take disciplined action. You’re never done renewing the company so that it might be built to last. You’re never done preparing for bad luck and capitalizing on good luck, getting a higher return on luck than others. Greatness is an inherently dynamic process, not an end point.

The Map doesn’t guarantee a great outcome. But those who adhere to its principles—and who do so with joyful intensity—have much better odds of building a great company that can endure than those who don’t. Along the way, perhaps as more of a by-product than a goal, they just might find the daily happiness that comes from doing meaningful work with people they truly like and deeply respect. And it’s hard to have a better life than that.

Businesses do not maximise anything. The most successful business leaders such as Marks or Walton or Gates pursued the unquantifiable, but entirely meaningful, objective of building a great business. A great business is very good at doing the things we expect it to do— rewarding its investors, providing satisfying employment, offering goods and services of good quality at reasonable prices, fulfilling a role in the community— and to fail in any of these is, in the long run, to fall in all of them.