Practice question · Multiple choice
A simulation can produce plausible-looking output while being completely wrong. What distinguishes verification from validation, and why are both needed?
Hints
- Two things can be wrong: the equations you chose, and the code that solves them. Which check catches which?
- Ask what a bug-free implementation of the wrong physics would produce.
Show the answer
A. Verification asks if the code implements the model; validation, if the model fits reality.
Why
Verification asks whether we are solving the equations right; validation asks whether they are the right equations, and they catch different failures. A flawless implementation of a model missing a force runs cleanly and produces confident nonsense. Which is why plausible output is weak evidence, a simulation is built to produce it, so 'the results look reasonable' begins the checking.
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