PRODUCT VARIETY AND DEMAND UNCERTAINTY: WHY MARKUPS VARY WITH QUALITY*
研究发现需求不确定性可以解释存在沉没成本时的均衡产品多样性，并揭示了企业产品线中质量与利润率的关系：高质量产品绝对利润高但百分比利润率低，低质量产品则相反。
We demonstrate that demand uncertainty can explain equilibrium product variety in the presence of sunk costs. Product variety is an efficient response to uncertainty because it reduces the expected costs associated with excess capacity. We find that within the firm's product line, the highest quality product has the highest profit margin but the lowest percentage margin, while the lowest quality product has the highest percentage margin but the lowest absolute margin. Both of these relationships are consistent with evidence available from marketing studies.