Calculating speed by mixing distance and time measurements from two different reference frames produces a valid result.

The claim suggests that mixing distance and time measurements from two different reference frames directly produces a valid speed result. In physics, particularly special relativity, quantities must be properly transformed using Lorentz transformations rather than naively combined across frames, as mismatched frames fail to account for relativity of simultaneity and time dilation. The retrieved papers emphasize the necessity of rigorous spacetime formulations and transformations (e.g., papers 0, 1, and 5). Thus, the claim is refuted.