Theories are predictive statements of what causes what, and why. Many managers view themselves as practical men and women and don’t view their actions as being guided by theory. But every plan that a manager makes and every action that a manager takes are, in fact, predicated on some theory in his or her mind—a belief that certain events or actions will result in particular outcomes. “If we cut price, more people will buy more” is an action predicated on a theory. “If I give her a performance-based financial incentive, she will work harder and more productively” is another. “If I out source this subsystem to a supplier that does the job more cost-effectively than we can do it in-house, we’ll be more competitive” is a third. These theories serve as mental maps guiding the everyday actions managers take.

Too often, though, managers aren’t even aware of these powerful mental maps—beliefs about cause and effect—that they employ when making plans and taking actions. Still, the maps are there, somewhere in the managers’ minds. Like it or not, every manager is, therefore, a theory-driven manager.

Most theories that managers use were formulated through experience—and because members of management teams experience many things in common, they end up employing similar theories, consciously or unconsciously, as they make decisions. Edgar Schein, Massachusetts Institute of Technology’s noted scholar of organizations, has shown how these shared theories develop and come to comprise an organization’s culture. ^[1] He notes that, in the earliest days of every organization’s history, there came a point when a group of people had to get something done. Confronted with that task, they put their heads together and figured out how they would approach the challenge. If their efforts failed, then the next time that task arose, they would be inclined to devise another way to get the job done. If that method proved successful, then the next time the task arose, the group would be inclined to use the same method to get the job done. If that method proved successful again when the same task arose, they would be even more likely to address the task with the same approach when it arose again, and so on.

Ultimately, if a group of people have successfully worked together in particular ways to address recurrent tasks again and again, they come simply to assume that this is the way they should do things. When this happens—when people begin adopting ways of working by assumption, rather than by explicit debate and decision—that process becomes part of the organization’s culture. This is what an organization’s culture is: ways of getting things done that a group of people have used so successfully for so long that they simply come to assume that doing things the same way is the only way to get the needed result. As a consequence, the more successful the organization is, the stronger will this unconscious consensus about cause and effect become. Another way to put it is that, because theories are statements of what causes what and why, an organization’s culture is actually a collection of theories in use. These theories provide valuable guidance to managers as they make plans and take actions, because they build on what individuals in the organization have learned from their collective experience. In fact, orga-nizations with strong cultures or theories in use become in many ways self-managing, because managers in disparate parts of the company can be trusted to make decisions autonomously that are consistent with what the company has learned will work.

All of this is good, of course, except when things change. Then the widely shared maps that managers have unconsciously used to predict what events and actions will produce the needed results may no longer hold true. This is why I’m delighted that Stewart and Hal have written this book. In its pages, they present methods for discovering the implicit theories in-use that managers have learned to trust in the course of building successful companies—theories that must be understood explicitly before new ones can be adopted in times of change.

No panaceas address any or all of the problems of management completely. I certainly hope that no one who reads this book has bought it to find an easy answer to the problems of managing change. But I do believe that when a talented group of managers can share a common language and a common way to frame the origin of the problems they face, they can do remarkable things. And I believe that Leading Strategic Change delivers essential methods that managers can employ to encourage these vital efforts.

Clayton M. Christensen

Robert & Jane Cizik Professor of Business Administration

Harvard Business School