This paper examines the social value of information in symmetric Bayesian games with quadratic payo↵ functions and normally distributed public and private signals. The main results identify necessary and su cient conditions for welfare to increase with public or private information. Using the conditions, we classify games into eight types by welfare e↵ects of information. In the first type, welfare necessarily increases with both public and private information.In the second type, welfare can decrease, but only with public information. In the third type, welfare can decrease as well as increase with both public and private information. In the fourth type, welfare can decrease with both, but can increase only with private information. The remaining four types are the counterparts of the above four types with the opposite welfare e↵ects of information. For each type, we characterize a socially optimal information structure and a socially optimal Bayesian correlated equilibrium.JEL classification: C72, D82.