Few phrases do more persuasive work than a relative change. 'Fifty percent better,' 'doubled,' 'reduced by a third' — these sound enormous. They can also describe a change so small in real terms that you would never notice it. The trick is that relative figures hide the size of the thing they are a percentage of.
Imagine an outcome that occurs in two people out of a hundred in one group and one person out of a hundred in another. That is a fifty percent relative reduction — a headline-grade number. In absolute terms it is one person in a hundred. Both descriptions are true. Only one of them tells you what to expect.
Relative changes are popular precisely because they are large and decontextualized. They travel well in marketing because they sound dramatic without committing to a baseline. The same result expressed in absolute terms is often modest enough that it would never have made the headline at all.
The reading move is to convert. Whenever you see a percentage improvement, ask: a percentage of what starting number? If a score rose by twenty percent, what was the score, and what does a change of that size feel like in practice? A big percentage of a small thing is still a small thing.
This is not an accusation that anyone is lying. Relative figures are legitimate and sometimes the right way to express a result. The problem is presenting only the relative figure, which lets a tiny absolute change wear a giant costume. When both are available, read the absolute one — it is the number that knows how big it really is.