By the end of this lesson, you should be able to:

Interpretive Structural Modeling (ISM)

Interpretive Structural Modeling is a “directed graphic representation of a particular relationship among all pairs of elements in a set to aid in structuring a complex issue area” (Porter, et al., 1980.)

Step 1. ISM Begins with an issue or problem.

Global Warming

Step 2. The elements that comprise the issue context are listed.

• Desertification
• Industrialization
• Population (human)
• Natural global climatic changes

Step 3. Pairs of elements are compared graphically or in a matrix, using an arrow to indicate "This element contributes more than that element." Draw a graphic representation.

For example, let's say we believe that Industrialization (I) is felt to contribute more to global warming than Desertification (D) or Natural global changes (N), and D were believed to contribute more than N. But Population (P) were believed to contribute more than any of the other three. The diagram would look like this:

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According to Porter, et al., (1980), ISM is useful in:

• problem definition and bounding
• impact evaluation
• identifying relationships among policy sectors

but its weaknesses include:

• It identifies static relationships (i.e., structural rather than dynamic relationships).
• It is qualitative, not quantitative.
• It is simplistic, and not very powerful.

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I wonder, would the inventor of ISM would agree with these criticisms? John Warfield has written extensively on ISM; he invented it during 1970 - 1973. He distributes free DOS software to facilitate its use at the following site (optional):

The course electronic reserve from Porter, et al., discusses ISM on pages 71 to 73 (optional):

BSU Electronic Reserve:
www.bsu.edu/pres/ereserves/P/erdata/JFlowers/ITEDU510/082700-7ET.pdf