<b>Why your fix won't show up for 28 days</b>

<b>Why your fix won't show up for 28 days</b>

Google's field data comes from CrUX — the Chrome User Experience Report — and it works on a rolling 28-day window. This trips up almost everyone who ships a fix.

Think of it like a class grade made from the last 28 days of quizzes. Ace today's quiz and your average barely moves, because 27 older days are still counted.

So when you fix LCP and the score doesn't budge tomorrow, nothing is broken — the old slow days are simply still in the mix.

1. Ship your fix and note the date.
2. Expect partial improvement around day 7 to 10.
3. Wait the full 28 days before judging whether it worked.

Try this: keep a tiny log of 'fixed X on this date'. Then you'll know exactly when to start celebrating, instead of panicking on day two.