1. A method executed in a computer system for estimating a probability that an event will occur, the method comprises: retrieving data as data strings from a data source; producing a dataset from the retrieved data strings; building a statistical model of parent-child relationships from data strings in the dataset by: determining incidence values for the data strings in the dataset; and concatenating the incident values with the data strings to provide child variables; analyzing the child variables and the parent variables to produce statistical relationships between the child variables and a parent variable; determining probabilities values based on the determined parent child relationships; and building an ontological representation of the data based on subsequent conditional probabilities values.