Market Structure Analysis provides an alternative to econometric analysis when adequate data is not available. It makes estimates of consumer responses based on information about competing brands like market shares, prices, and marketing spending. The key assumption is that brands within a "partially-competing set" are distributed randomly around the optimal pricing and spending points for that set. This allows estimating a brand's response to changes in its own or competitors' prices and marketing spending. The approach models competition between brands to different degrees and can be used to inform pricing, promotion, and advertising decisions.