What They Actually Are
Largest Contentful Paint is how long until the main content appears. Under 2.5 seconds is the target. This is what people mean by loading speed.
Interaction to Next Paint is how quickly the page responds when somebody taps or clicks. Under 200 milliseconds. It replaced an earlier measure and is stricter, so scores that were fine may not be.
Cumulative Layout Shift is how much the page moves around while loading. Under 0.1. This is the one everyone has experienced: reaching for a button as an advert loads above it and pushing it out of the way.
How Much They Affect Rankings
Less than the amount of attention they receive. They are a ranking signal and a weak one, used mainly as a tiebreaker between pages of otherwise similar relevance.
A slow page with the best answer will still outrank a fast page with a worse one. Nobody has been rescued from irrelevance by improving these scores.
So the honest reason to care is not ranking. It is that the same things they measure affect whether visitors stay, which affects enquiries directly. That is a better argument and it does not depend on a search engine’s weighting.
The One Most Sites Fail
Layout shift is the most commonly failed and the least commonly prioritised, which is unfortunate because it is both the most annoying for users and often the easiest to fix.
The causes are consistent: images and video without dimensions specified, so the browser does not reserve space; advertisements and embeds inserted after load; fonts loading late and reflowing the text; banners injected at the top of the page.
Most are addressed by declaring the space something will occupy before it arrives. That is a small amount of work with a disproportionate effect on how a site feels.
What To Ask
- Are we looking at lab data or real users? Tools that test a page in a controlled environment give a different answer from what visitors actually experience. Field data from real visitors is what counts and what Google uses.
- What do the mobile scores look like? Almost always worse, and mobile is where most traffic is.
- What is causing the layout shift? Usually two or three specific elements.
- Which pages matter? The homepage and the pages that produce enquiries. Optimising an obscure page is effort spent nowhere.
Where The Time Is Actually Going
On most sites, particularly WordPress ones, the causes are unglamorous and repeat.
Images that are far larger than the space they are displayed in. Too many plugins each adding scripts and stylesheets. Third-party tags: analytics, chat, heatmaps, advertising pixels, each adding requests outside your control. Fonts loaded from elsewhere. No caching.
The third-party category is the one worth examining first, because it is usually the largest contributor and the easiest to reduce. Most sites are carrying tags added for a campaign that ended, and nobody removes them.
The Sensible Position
Worth getting into reasonable shape, particularly on mobile and particularly on the pages that convert. Not worth an expensive programme chasing perfect scores.
The realistic benefit is a site that feels quick and does not move under the visitor’s finger, which shows up in conversion rather than in rankings. Judge the work on that.
More terms are in the glossary.
