Forwardlooking
retrospective
图5-2 经济成本 vs. 会计成本
• 经济利润与会计利润
收益经济利润=收益- 经济成本
（机会成本总和） 机会成本总和）
收益会计利润=收益- 会计成本
（显性成本） 显性成本）
3、机会成本vs.沉没成本 • 机会成本（opportunity cost） ）
the personal computer industry
(where most costs are variable) • Companies like Dell, Compaq, and IBM produce millions of personal computers every year. Because the computers they produce are very similar, competition is intense, and profitability depend critically on the ability to keep costs down. Most of these cost are variable – they increase in proportion to the number of computer produced each year. Most important is the cost of components: the microprocess that does much of the actual computation, memory chips, hard disk drives and other storage device, video and sound cards, etc. Typically, the majority of these components are purchased from outside suppliers in quantities that depend on the number of computers produced.
