Most accidents in well-designed systems involve two or more events of low probability occurring in the worst possible combination. - Robert E. Machol

A new concept and a new method were needed. The concept from the engineering standpoint is the evolution of the engineering scientist, i.e., the scientific generalist who maintains a broad outlook. The method is that of the team approach. On large-scale-system problems, teams of scientists and engineers, generalists as well as specialists, exert their joint efforts to find a solution and physically realize it. We are led to the concept of the system-design team, a small group of engineers or scientists, to lead a large project and organize the system effort. Such men have been variously called engineering scientists, system engineers, system analysts, or large-scale-system designers. The technique has been variously called the systems approach or the team development method. It is toward this man and his teammates that these discussions are directed. With the realization that not enough can be learned in all the required fields to make him a specialist, enough is introduced to make him aware of the language and problems of the specialist. This generalist is a new quantity in the engineering world, and his education must be begun.

The conclusions of most good operations research studies are obvious.

The lack of formal definition does not prevent us from noting the characteristics which are frequently present in large scale systems. Each such system has a certain integrity. It may or may not be rigidly controlled from some central point, but in every case, all the parts of the system have some common purpose; in some sense, they all contribute to the production of a single set of optimum outputs from the given set of inputs, with respect to some appropriate measure of effectiveness.