Introduction to Industrial Engineering

By Jane M. Fraser

Chapter 5

The IE Approach

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5.2 Systems thinking

The educational system in the US has these parts:

We call this list of parts a “system” because the parts interact with each other to achieve overall goals, such as an educated population. The parts may interact through cause and effect or through the exchange of information or material. We can think of the input and output of the overall system, and we can also think about the input and output of each part; for example, some of the students who graduate from middle school (an output) go on to high school (an input). We can also think of the parts as being processes in the educational system.

Feigenbaum defines a system as:

“a group or work pattern of interacting human and machine activities, directed by information, which operate on and/or direct material, information, energy, and/or humans to achieve a common specific purpose or objective.” (page 92)

Clearly this definition relates closely to industrial engineering and explains why some industrial engineering departments are called industrial and systems engineering. However, systems engineering is also used sometimes in a more limited meaning, to refer to designing a computer and information system.

When we define a system we implicitly draw a line around some parts to include those parts and to exclude others. For example, the educational system includes the schools, but not the roads students travel on to get to school or the organizations that employ students after they graduate. Generally, looking at a larger system is more accurate but harder. We can understand some aspects of the educational system without considering these other parts, but some aspects require looking at the larger system. We can still examine the educational system if we remember to include in our study its interactions with its environment, such as the transportation system and the employment system.

For the IE, the systems approach is important because it reminds us to consider the environment surrounding the system we are studying and to move the boundaries outward as much as possible so that we consider a problem in its larger context.

Some systems have feedback. A thermostat is an example of a system in which negative feedback helps the system maintain a set temperature; the feedback is called "negative" because an increase in temperature leads to a decrease in heating. The educational system doesn’t tend to have a lot of feedback and that may hamper improvement of the system. Have you ever been asked by your high school to give feedback on how well your education prepared you for college or for work?

The operation of a system that has evolved without conscious design or a system that has been designed piece by piece almost always can be improved. Analysis means to take a system apart in order to understand how the parts work; systems thinking stresses synthesis, that is, understanding how the parts work together and how the system works as a whole. Understanding how each part of the educational system works is not enough for a good understanding and certainly not enough for making recommendations for improving the educational system; better recommendations would come from understanding how the parts of the system work together also.

A system has the property that a change to one part can have effects, sometimes surprising effects, on other parts. A state might require that students entering state-funded four year universities meet certain standards (for example, knowledge of a foreign language). The effects of such a change might be good for the universities, but the effects on the high schools must also be considered; they might, for example, have to provide more language classes. Improving one part of system may have good or bad consequences on another part of the system. Using antibiotics to cure diseases has had the consequence of creating bacteria that are immune to some antibiotics; within the system of individual patient and doctor, having the patient take antibiotics makes sense, but in the larger system, we might want to be more cautious about their use.

A system may have emergent properties, that is, properties of the whole that are not the property of any part. For example, living systems are alive, but one can’t isolate that property in any part of the system; it is a property of the entire system.

Turner et al. (page 38) classify systems these ways:

[Systems approach. Churchman? Others?]

Certain types of systems with feedback occur frequently in organizations and in society. If you learn to recognize them, you can learn what actions to take. William Braun describes 10 system archetypes:

Read the section about the first archetype, Limits to Growth. This web page has a summary of the above models.

In this book The Fifth Discipline, Peter Senge argues that organizations must become learning organizations by building knowledge of four disciplines: personal mastery, mental models, shared vision, and team learning. The "fifth discipline" is systems thinking, and he gives these laws of complex systems:

  1. "Today's problems comes from yesterday's 'solutions.'" Solutions can have unintended and undesired effects.
  2. "The harder you push, the harder the system pushed back." "Compensating feedback" may keep a system in the state it started.
  3. "Behavior grows better before it grows worse." Actions that make short term improvement may cause long term disaster.
  4. "The easy way out usually leads back in." Easy and obvious solutions would have been done already if they would have worked. Hard work is needed to find the real solution.
  5. "The cure can be worse than the disease." Some easy solutions become addictive.
  6. "Faster is slower." Any organization has an optimal rate of growth.
  7. "Cause and effect are not closely related in time and space."
  8. "Small changes can produce big results - but the areas of highest leverage are often the least obvious."
  9. "You can have your cake and eat it too - but not at once." For example, an improvement in quality pays off eventually in improved profits.
  10. "Dividing an elephant in half does not produce two small elephants." Some problems must be solved by improving the whole system.
  11. "There is no blame." "You and the cause of your problems are part of a single system."

While most engineers design physical objects (cars, bridges, and so forth), IEs design and improve production systems. A production system is a system that produces goods or services for customers. IEs have to think about how a production system works as a system by using the types of ideas I've just described.

The history of engineering often emphasizes the design of objects, but Thomas P. Hughes argues that the important inventors in the 20th century were actually builders of systems, not just inventors of objects. Hughes wrote:

“To associate modern technology with individual machines and devices is to overlook deeper currents of modern technology that gathered strength and direction during the half-century after Thomas Edison established his invention factory at Menlo Park. ... Large systems -- energy, production, communication, and transportation -- compose the essence of modern technology.” (pages 184-185)’

Hughes argues that Edison was concerned with the electric system not just the lightbulb. Hughes gives this quote from Edison’s papers:

“It was not only necessary that the lamps should give light and the dynamos generate current, but the lamps must be adapted to the current of the dynamos, and the dynamos must be constructed to give the character of current required by the lamps, and likewise all parts of the system must be constructed with reference to all other parts, since, in one sense, all the parts form one machine, and the connections between the parts being electrical instead of mechanical. Like any other machine the failure of one part to cooperate properly with the other part disorganizes the whole and renders it inoperative for the purpose intended.

“The problem then that I undertook to solve was stated generally, the production of the multifarious apparatus, methods, and devices, each adapted for use with every other, and all forming a comprehensive system.” (Hughes page 73)

Hughes argues that, like Edison, Ford was a system builder, a builder of a production system:

“[From 1910 to 1913] Ford and a few like-visioned mechanics and self-educated engineers created at his Highland Park plant a system of mass production unlike any the world had even seen. They established a finely directed, controlled, and steady flow of energy and materials on a scale then unprecedented.” (Hughes, page 203).