Related: Core Web Vitals and Lighthouse Explained covers how Google measures performance in the field, including how perceived performance metrics like INP differ from load metrics. Two pages load in exactly the same amount of time. One shows a spinner. The other shows a skeleton screen. Users consistently rate the skeleton screen page as faster, even when it is not. This is not a quirk or a fluke. LinkedIn documented it, researchers replicated it, and it has a straightforward neurological explanation. Understanding why it works also explains when it does not, and why getting this wrong can make a genuinely fast page feel slow. What this covers: Why spinners and skeleton screens produce different perceived wait times at identical actual load times, what LinkedIn's research found, when to use each pattern, and a CSS-only skeleton implementation that does not require a library. The LinkedIn research In 2013, LinkedIn redesigned their mobile apps and faced a choice about loading states.…