A low degree of social mobility may be an indicator that the idea of careers open to talents is significantly violated. Children of poor families are not eligible to apply for plummy positions, or if they are eligible and do apply, their applications are discounted, not fairly assessed on their merits with a guide to choosing who gets offered the positions. A low degree of social mobility might also be an indicator the society fails by a very wide margin to satisfy FEO. Of course learning that society fails to satisfy FEO would hardly be a surprise: surely no modern society has ever done so.  But a society might be closer or further from satisfying FEO, and low social mobility might indicate that the society's divergence from FEO is very large indeed.