The current theoretical analysis of labor market search and matching is dominated by two rather separate literatures. In the first of these one typically assumes firm wage posting. Wage dispersion may then result from either on-the-job worker search (Burdett and Mortensen (1998), Burdett and Coles (2003)), or from nonsequential search whereby workers find it advantageous to search for more than one firm simultaneously. Wilde (1977) and Burdett and Judd (1983) provide product market applications of the latter type of models; more recently, Acemoglu and Shimer (2000) (hereafter AS) and Mortensen (1998) have studied labor market applications. In AS, wage dispersion among identical workers can result from firms’ endogenous capital choices, whereby some firms invest more capital than others, and offer a higher wage, in return for greater probability of employing a worker.
The other main branch of this literature assumes bilateral matching and bargaining between individual firms and workers, and builds on the work of Mortensen and Pissarides and followers (e.g. Mortensen and Pissarides (1999), Pissarides (2000); see also Acemoglu and Shimer (1999)). This model framework assumes continuous time, unlimited decision horizon and sequential search. Firms’ capital choices and wages are here typically identical.