| 
         Optimal Unemployment Insurance with Endogenous Search Effort  | 
    
| 
         Ping Yan  | 
    
| 
         In the framework of a search and matching model, when search effort
        enters the labor market matching function, search effort by one worker generates
        a negative externality on other workers searching for jobs. The solution to
        the social planner's problem may not be decentralized in a competitive
        market. Calibration shows that the current US unemployment insurance (UI)
        system generates an 8.07% welfare loss relative to the socially optimal
        allocation. An alternative scheme with higher replacement rate and lower wage,
        which achieves the highest welfare level among all competitive equilibria with
        unemployment insurance, leads to a welfare loss of only 1.18%.  | 
    
| Key Words: Matching function; Search effort; Unemployment insurance. | 
| JEL Classification Numbers: J38, J30. |