It is clear from the previous chapters of this book that both fault-injection techniques and analytical approaches for cross-layer reliability analysis have both positive and negative aspects that must be carefully analyzed whenever choosing the best approach to evaluate the reliability of a computing system, and none of them alone represents an optimal solution. With the increasing complexity of future computing systems, analyzing the impact on system reliability of any change in the technology, circuit, microarchitecture and software is a critical and complex design task that requires proper tools and models. The adoption of cross-layer reliability techniques makes this analysis even more complex and challenging. Therefore, there is an increasing interest into stochastic reliability models that are able to combine the benefit of fault-injection techniques at different abstraction levels and analytical approaches such as Register Data Lifetime [1] or Architectural Correct Execution [2-4] analysis into a unified stochastic model that is able to cope with the complexity of the target design together. This is favored by an increasing discussion on the use of these models in the framework of relevant reliability and safety-related standards such as the IEC 61508 [5] and ISO 26262 [6].