4
Rating Migrations
4.1
Rating Transition Probabilities
4.2
Analyzing the Time-Stability of Transition Probabilities
4.2.1
Aggregation over Periods
4.2.2
Are the Transition Probabilities Stationary?
4.2.3
Computation and Quantlets
4.2.4
Examples with Graphical Presentation
4.3
Multi-Period Transitions
Bibliography