In Hall thrusters and some other EP devices, the rate of electron transport across magnetic field lines is orders of magnitude higher than classical collisionality would suggest. The reasons for this are unknown, and there are no first-principles models that can predict this enhanced anomalous electron transport. Without an understanding or a good approximation of this non-classical transport, it is impossible to self-consistently predict thruster performance. Therefore, understanding anomalous transport in EP devices is one the single most important open questions in the field today.