We introduce skill groups and different production technologies into the Burdett-Mortensen model of on the job search. Supermodularity of the different skill groups in the production process leads to a positive intra-firm wage correlation between skill groups. Increasing returns to scale allow...

We develop and estimate a structural non-stationary econometric model of job search with monitoring of search effort and sanctions. The earliest moment of the first monitoring is announced several months in advance and the judgement of the caseworker is based on cumulated search effort over a...