Summary
Engagement and page relevance ultimately determines SEO ranking
Lighthouse and Page Speed scores are not used to rank pages - they are only tools to assess load time blockers and highlight technical optimization opportunities. Page Experience is a better guide to actual real-world impacts
A personalized user experience has a direct impact on engagement signals, the core ranking metric, and likely has a greater impact on overall ranking and SEO
LimeSpot Apps are monitored and optimized to have a minimal impact on load times and have been independently tested for ecommerce performance.
Website segmentation and personalization can have a larger impact on improving user engagement signals, ultimately leading to improved SEO ranking and greater sales.
Technical SEO Optimization Tools
Lighthouse, PageSpeed Insights and Google Search Console Core Web Vitals (Page Experience)
Lighthouse data is a great tool to use and measure changes with detailed results, however, it is not considering ‘real-world data’ and is not used by Google to assess rankings. Lighthouse and eCommerce
PageSpeed Insights is a blend of lab and real-world data and may give you a better idea of overall performance.
A better indicator of impact to your site’s SEO is the Core Web Vitals, which include Largest Contentful Paint (LCP), Cumulative Layout Shift (CLS), First Input Delay (FID), and can be found in your Google Search Console. Keep in mind your site may not be generating enough field data to even calculate Core Web Vitals scores.
The chance of a bounce increased by 32% when a page load time went from one to three seconds, and 90% when page load time went from one second to five seconds. Load times can also impact time on site (Avg. Session Duration) and Pages per Session, with both metrics seeing a decrease as load times increase according to Google.
Engagement vs. Speed for SEO
That being said Google has made it very clear that the most important ranking feature of any page is engagement, of which speed (or page experience) is only a small piece of. Just take a look at the top search results of any query, most of the top results have nowhere near perfect Lighthouse or PageSpeed scores.
Engagement encompasses several different metrics including Click-Through Rates (CTRs), Inbound Links, and Dwell time. These can easily be measured through site analytics as Pageviews, Returning Visitors, Bounce Rate, Time on Site, and Conversions. A Bounce Rate is the percentage of users who leave your site without performing an action such as clicking a link or submitting a form.
One contributing factor impacting Bounce Rates is load time or page speed, which has been a factor in search for some time. This has increasingly become a focus of SEO tools as it is easily identified and linked with engagement.
While page speed has a very direct impact on bounce/abandonment rates, page relevance and user engagement have the ultimate say in the overall ranking of the page. A more personalized user experience will likely have much more of an impact than a few milliseconds of load time or a lower Lighthouse/PageSpeed score.
What does Google Say about Lighthouse and PageSpeed Scores?
Google relies on field data gathered from real visitors, which can vary widely from lab data sources like Lighthouse. Additionally, any increase or decrease in scores, regardless of tool or source, does not supersede relevance.
Google’s John Mueller has stated (via reddit r/SEO):
"Google doesn't use the X/100 lighthouse score for search, we use the core web vitals separately (lcp, cls, fid)."
"Core web vitals / page experience doesn't replace relevance, but it's also more than just a tie-breaker. For competitive queries, you might see some effects. If someone's looking for your business name, it's less important. Check the queries you rank for and guestimate based on that."
In fact their own patents describe how user intent and interaction data is collected and used to determine search rank.
Conclusion
SEO is a complex thing and changes rapidly, and while site speed will likely always have an impact, the best way to measure actual page performance is by looking for:
A Decrease in Bounce Rates
An Increase in Time on Site
An Increase in Pages per Visit or Pages per Session
An Increase in Conversions
These engagement metrics will have a direct effect on your SEO rankings and you will likely see an increase in organic traffic over time as they improve. More importantly, with optimized customer experiences, you will also see an increase in sales, AOV, revenue, and returning customers.