The source of correlation for the signals from detectors in the presence of a stochastic neutron field is analyzed for a variety of circumstances. A general methodology, based on a master equation approach, is compared with the Langevin/Schottky method with the result that there is consistency if the detection process is included in detail. For cases where the detector removes the detected neutron, the only sources of correlation are elementary processes that produce more than one neutron; consequently, the Schottky prescription for the noise equivalent source must be corrected accordingly. An additional term because of the finite electronic resolution is also found and added to the noise equivalent source. Because of the relevance of the subject to the theory of the 252Cf source noise method to measure reactivities, the general results are applied to interpret a recently performed experiment with this type of source.