Effective control of spinning reserve (SR) is important for economic advanced dispatch (AD). In the conventional AD methods, the SR allocation based on deterministic criterion is hard to keep system response risk within a specified level. So, in this paper, expected demand not supplied (EDNS) is introduced to AD as an index for response risk, and a given EDNS limit is treated as a constraint of AD. The resulted AD with equal response risk model forms a {0, 1} mixed integer programming (MIP) problem. Additional constraints for {0, 1} variables are then used to transform the {0, 1} MIP problem to quadratically constrained quadratic program (QCQP) problem. The decoupled primal-dual interior point method is then used to achieve solutions. Test results show the efficiency of the proposed method.