Algorithmic stability is a central notion in learning theory that quantifies the sensitivity of an algorithm to small changes in the training data.
Recent results establish that testing the stability of a black-box algorithm is impossible, given limited data from an unknown distribution.
This work examines the hardness of testing algorithmic stability in a broad range of settings, including categorical data.
The study finds that if the available data is limited, exhaustive search is essentially the only universally valid mechanism for certifying algorithmic stability, implying fundamental limits on stability testing.