We compare two commonly used mechanisms in procurement: auctions and negotiations. The execution of the procurement mechanism is delegated to an agent of the buyer. The agent has private information about the buyer s preferences and may collude with one of the sellers. We provide a precise...

This paper uses panel data from the German Socio-Economic Panel (SOEP) to analyze welfare entry and exit among natives and immigrants after a substantial reform of the welfare system (``Hartz reform''). Using results from dynamic multinomial logit models, we calculate transition matrices between...