Module 2: External analysis What is an industry? Why do firms need to define their industry carefully? What are Porter's Five Forces shaping industry profitability? What factors are included in each of these forces? What is the difference between rivalry, new entrants, and substitutes? Which factors are included in the general environment (PEST) that influence industry growth or decline? How do strategic groups change competition? What prevents firms from changing to a different strategic group? What are some key assumptions underlying external analysis? How does market structure to help better understand competition among firms