Many workers believe that personal contacts are crucial for obtaining
jobs in high-wage sectors. On the other hand, firms in high-wage sectors
report using employee referrals because they help provide screening and
monitoring of new employees. This paper develops a matching model that
can explain the link between inter-industry wage differentials and use
of employee referrals. Referrals lower monitoring costs because high-effort
referees can exert peer pressure on co-workers, allowing firms to pay lower
efficiency wages. On the other hand, informal search provides fewer job and
applicant contacts than formal methods (e.g., newspaper ads). In equilibrium,
the matching process generates segmentation in the labor market because
of heterogeneity in the size of referral networks. Referrals match good
high-paying jobs to well-connected workers, while formal methods match
less attractive jobs to less-connected workers. Industry-level data show a
positive correlation between industry wage premia and use of employee
referrals. Moreover, evidence using the NLSY shows similar positive and
significant OLS and fixed-effects estimates of the returns to employee
referrals, but insignificant effects once sector of employment is controlled
for. This evidence suggests referred workers earn higher wages not because
of higher unobserved ability or better matches but rather because they
are hired in high-wage sectors.