Explaining the value Google Lighthouse ratings to a client?


I am a web developer who is planning to take on some freelance projects soon. I have a few contacts who own small businesses and are keen to have their ecommerce websites redesigned and rebuilt.

One thing I would like to do is run Google Lighthouse audits on the existing websites and hopefully improve these scores during the rebuild. However I would like to be able to communicate the value of these scores to a customer.

So what is the business value for each of the following scores in Google Lighthouse:
Best Practices


Re performance: for initial load, you’ve got about 375ms (time to glass, ie showing something meaningful) before user attention starts to wander. Same for UI responsiveness, otherwise it’s going to feel sluggish. This has direct impact on whether people stay interacting with the site/app – business value should be evident (this can be backed up by using analytics to get concrete figures, though have to be careful that adding those doesn’t itself impact performance)

As a rule of thumb, structuring an app for accessibility will improve usability for all users. But having an app be accessible means it works for all users regardless of any disabilities (more users, better word of mouth). Also generally means it will comply with laws/legal recommendations. One biggie is colour: 10% of the population is colourblind to some extent, so ensuring colour accessibility has a pretty immediate effect.

SEO should be self explanatory: if it’s a site, the owner normally wants it as close to being the first result on Google as possible