Porter's four corners model is a predictive tool designed by Michael Porter that helps in determining a competitor's course of action. Unlike other predictive models which predominantly rely on a firm's current strategy and capabilities to determine future strategy, Porter's model additionally calls for an understanding of what motivates the competitor. This added dimension of understanding a competitor's internal culture, value system, mindset, and assumptions helps in determining a much more accurate and realistic reading of a competitor's possible reactions in a given situation.