1. A system for the prediction of a target slot value of a user goal, comprising: a user data store that stores information regarding user behavior, the information comprising a plurality of features associated with a user's behavior comprising at least one or more of a periodic feature, a contact-specific feature, a predicate-related feature, a time-related feature and a device-related feature, at least the periodic feature and the time-related feature being independent of content that is included in a user input; and an argument model that employs statistical modeling and the information stored in the user data store, the argument model is applied to each of a set of slot values to predict the target slot value by: for each of the set of slot values, determining a probability that the particular slot value is the target slot value, normalizing the probabilities of all of the slot values to infer a probability distribution over all of the slot values, and identifying the target slot value using the inferred probability distribution.
3. The system of claim 1 , wherein the argument model for unseen values is uniform.