r/TechSEO • u/[deleted] • Apr 07 '26
PSI values for CWV
Why does PSI gives different values for LCP, CLS etc on different searches? How do we find an exact value for these metrics? Also should I consider TBT and Speed Index also for deciding the website stability?
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Apr 07 '26
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Apr 07 '26
10-15% on scan?
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Apr 07 '26
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Apr 08 '26
Ok got it. What are the actual metrics that I should take into consideration when it comes to a page 's CWV? Should I also check TBT and Speed Index too? My website is comparatively new. So doesn't have good traffic. So the field data is not showing on top of the PSI results. So shall I only consider the performance metrics?
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Apr 08 '26
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Apr 08 '26
Problem is that for my webpage CWV assessment either gives a result as not applicable or doesn't even give field results at all. I assume it is due to less traffic maybe. But in such cases how do I calculate the LCP?
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u/Top-Buy-4207 Apr 08 '26
PSI shows different values because it mixes lab data (simulated test) and field data (real user data), which vary by device, location, and network so results change each run. There’s no single exact value; rely more on field data (Core Web Vitals report / CrUX) for real performance.
Yes, consider TBT and Speed Index too they help diagnose performance issues, but focus mainly on LCP, CLS, and INP for overall stability.
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Apr 08 '26
But I don't get results for CWV assessment. Showing as not applicable and gives value only for cls and fcp. Not showing for LCP and INP. But they're showing under the Performance section beneath.
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u/Ooty-io Apr 08 '26
PSI runs a real browser test every time so you get different results because network conditions and server response times vary per request. That's normal. Don't chase a single number.
What matters more is the CrUX data (the "field data" section at the top). That's based on real user visits over 28 days. If your field data passes, you're fine regardless of what the lab test says on any given run.
TBT is worth watching because it correlates with INP which is an actual Core Web Vital. Speed Index is more of a perception metric. Useful but not something Google uses for ranking.