Abstract. The adiabatic theorem gives conditions that guarantee that a system defined by Schrödinger's equation remains in its ground state when started in its ground state and evolved slowly. Realistically, such systems are subject to perturbations in the initial condition, systematic time-dependent perturbations in the Hamiltonian, coupling to low-energy quantum systems, and decoherent time-dependent perturbations in the Hamiltonian. Using Wilkinson-style perturbation analysis, we derive bounds on the effects of these perturbations. This is joint work with Michael J. O'Hara.