I don't know, that's like saying that the one way to measure quality of journalism is by number of clicks.
Good UX should help conversion rate, but so might dark patterns, obnoxious popups, lies, etc.
Good UX should help conversion rate, but so might dark patterns, obnoxious popups, lies, etc.
Otherwise, it just becomes an art discussion which can be amusing but hardly something you can build a business on.
For a newspaper, you could also have whether users feel more informed, whether they are more informed, etc.