11. A system comprising: one or more processing devices; and one or more non-transitory computer-readable media coupled to the one or more processing devices having instructions stored thereon which, when executed by the one or more processing devices, cause the one or more processing devices to perform operations comprising: determining a relational event history based on a data set, the relational event history comprising a set of relational events that occurred in time among a set of actors; populating data in a probability model based on the relational event history, wherein the probability model is formulated as a series of conditional probabilities that correspond to a set of sequential decisions by an actor for each relational event, wherein the probability model includes one or more statistical parameters and corresponding statistics, and wherein at least one of the one or more statistics is determined using a decay function; determining, by one or more processing devices, a baseline communications behavior for the relational event history based on the populated probability model, wherein the baseline comprises a first set of values for the one or more statistical parameters; and determining, based on a second set of values for the statistical parameters, departures from the baseline communications behavior within the relational event history, wherein the second set of values for the statistical parameters are determined based on one or more subsets of the relational events included in the relational event history.
13. The system of claim 11 , wherein, to determine the at least one statistic using a decay function, the method comprises: selecting a subset of one or more relational events from the relational event history; determining, based on the decay function, weights for the one or more relational events contained in the selected subset of relational events; weighting the selected subset of relational events based on the determined weights; and determining, based on the weighted relational events, the at least one statistic.