Sources of Power

There are many things experts can see that are invisible to everyone else:
Patterns that novices do not notice.
Anomalies—events that did not happen and other violations of expectancies.
The big picture (situation awareness).
The way things work.
Opportunities and improvisations.
Events that either already happened (the past) or are going to happen (the future).
Differences that are too small for novices to detect.
Their own limitations.

Key Points

Most problems are ill defined. Most studies of problem solving use well-defined goals.
To solve an ill-defined problem, we have to clarify the goal even as we are trying to achieve it, rather than keeping the goal constant.
Experience is needed to make a variety of judgments, ranging from identifying opportunities to gauging the solvability of a problem.
Artificial tasks do not require domain experience to arrive at solutions, and classical accounts usually ignore opportunities.
Experienced problem solvers can distinguish genuine anomalies from transients. Artificial tasks give the problem to subjects, thereby ignoring the process of problem finding.
Structuring a problem is using a barrier or leverage point to construct a course of action, not organizing a problem into a space that can be searched efficiently.
Standard advice on problem solving is aimed at well-defined goals and can interfere with solving ill-defined problems.
Problem solving is a constructive process. Computational approaches to problem solving rely on procedures, such as searching through problem spaces, that have little psychological reality.

Even brainstorming, a method that has been around for decades, seems primarily a social activity. If the participants generate their ideas individually, the resulting set of suggestions is usually longer and more varied than when everyone works together. Mullen, Johnson, and Salas (1991) have documented the finding that brainstorming reduces productivity.