A web server includes a web application being accessed by a plurality of users, and a processor that logs application inputs and outputs during a respective user session for each user, and creates a state diagram for each user during the respective user session based on the logged application inputs and outputs. Each state diagram represents states and transitions between the states. The processor translates each state diagram into vector space constructed by a sum of transition sequences defined by the transitions between the states, clusters similar transition sequences in each state diagram, and reduces each cluster of similar transition sequences in each state diagram into a single transition sequence. A reduced state diagram is generated for each state diagram based on the single transition sequences. The reduced state diagrams are analyzed to generate a predictive model representing a probability of state transitions between the different states.