Possible changes in the long-range disorder in hydrogenated amorphous silicon (a-Si:H) in association with light-induced defect creation (the Staebler–Wronski effect) have been investigated by combining measurements of the thermopower and conductivity activation energy differences with that of the conductance 1/ f noise. There is no observed change in the long-ranged disorder after twenty hours exposure to heat-filtered white light for a series of n-type-doped a-Si:H films.