On the Variability of AI-based Software Systems Due to Environment Configurations

Software systems are inherently complex. In addition, any ML model is, at its core, probabilistic in nature and hence, suffers from the challenge of uncertainty [2, 3, 4]. The complexity of a software system combined with the non-deterministic nature of an ML model can introduce variability - the phenomenon where a piece of software behaves differently when the development or the runtime environment changes although the internal software artifacts such as code, and input data are exactly the same. In practice it is very likely that development and deployment environments are different, hence, understanding how an ML model may behave differently after deployment compared to how it behaved in the development environment is a crucial aspect of AI-based software development. For example, an arbitrary face recognition system achieving an F1-score of, say 0.9, in the development environment does not guarantee that it will on average achieve a similar F1-score once deployed in a different environment configuration.