1. A method 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.