The literature on gradual typing presents three fundamentally different ways of thinking about the integrity of programs that combine statically typed and dynamically typed code. This paper presents a uniform semantic framework that explains all three approaches, illustrates how each approach affects a developer's work, and adds a systematic performance comparison for a single implementation platform.

@article{paperbot280,
  title = {A spectrum of type soundness and performance},
  author = {Ben Greenman and Matthias Felleisen},
  journal = {Proceedings of the ACM on Programming Languages},
  volume = {2},
  number = {ICFP},
  year = {2018},
  doi = {10.1145/3236766}
}