External analysis identifies opportunities and threats in an organization's industry environment. It analyzes industry dynamics to understand competitive forces like new entrants, substitute products, and supplier and buyer bargaining power. Opportunities arise when favorable conditions allow more profitability, while threats endanger profits. Industries are groups of similar substitutable products, and sectors contain related industries. Porter's five forces model is used to assess competition. The strength of these forces changes over an industry's life cycle from embryonic to decline. Macro trends like technology and regulation can also impact industry attractiveness and company strengths.