Identifying mobility barriers
利用PIMS数据库，研究行业内利润差异的持续因素，发现差异化因素比成本因素更能解释利润差异，且差异化优势多体现为更高利润率或市场份额。
Abstract This paper uses a new (PIMS) research data base to identify the mobility barriers–the factors associated with sustained intraindustry profit differentials–in a cross‐section of industries. The exercise suggests that differentiation‐related factors play more of a role in generating intraindustry profit differentials than do cost‐related ones. It also indicates that differentiation‐related advantages tend to be absorbed into fatter margins and (in some instances) larger maket shares, while cost‐related advantages are taken primarily in the form of increases in market share.