Michael Porter's five-force strategic analysis ... most of the five forces have a strong influence. The fast food industry is Porter's own example, which still remains the case.

However, the shrewdest investors will go beyond looking at Delta's financial position and will study ... forces on the company's health. One of the most effective tools for this is Porter's Five ...

There are different ways to analyze companies and their stocks. One is through an analysis using Porter's Five Forces Model, a methodology that looks at external factors within a specific industry.