Motivated by the growing desire for low power design as well as the stochastic behavior of electronic circuits, the probabilistic computing based on inherently stochastic devices has been proposed. The single-electron (SE) technology is a promising candidate for implementing probabilistic switches due to its intrinsic mechanism and nanoscale feature size. In this paper, we analyze the stochastic behavior of SE threshold logic, and quantitatively show that the switching energy consumed by an SE logic component increases with its reliability. Also studied is the energy-performance tradeoff for SE threshold logic. Simulation results are provided to verify the accuracy of our analysis.