have an impact

To have an impact is to make a strong difference to something. Not a nudge — the kind of change people notice and talk about afterwards.

It takes on: on the town, on her health, on the figures. The word is a collision at heart, so the phrase is stronger than have an effect and carries no direction with it — an impact can be good or ruinous, which is why the adjective in front is doing most of the work. Beware the verb impact on, which a great many readers still hear as management jargon; make a difference is the plain alternative.