# Does fixing your website pay off? What published studies show for speed, SEO and accessibility

Source: https://www.fixreports.com/blog/website-fixes-business-impact-evidence

Updated 2026-10-26

Nobody can honestly tell you how much your store will grow if you fix its speed, SEO or accessibility: the effect depends on your traffic, your products and how bad the problems are today. What exists is a body of published measurements from companies that made these changes and reported the results, some from controlled A/B tests. This guide collects the ones with a public source, says how each was measured, and shows how to estimate and then measure the effect on your own site with your own numbers.

**Key points**

- In a 50/50 A/B test, Vodafone's landing page with a 31% better LCP produced 8% more sales ([web.dev](https://web.dev/case-studies/vodafone)).
- In a month-long A/B test, Rakuten 24's page optimized for Core Web Vitals had 53.37% higher revenue per visitor and a 33.13% higher conversion rate ([web.dev](https://web.dev/case-studies/rakuten)).
- A Google-commissioned study by Deloitte across 37 brand sites linked a 0.1-second mobile speed improvement to 8.4% more retail conversions; it is correlational, not a controlled test ([web.dev](https://web.dev/case-studies/milliseconds-make-millions)).
- Google's own case studies report 25% to 82% higher click-through rates for pages with structured data or rich results ([Google Search Central](https://developers.google.com/search/docs/appearance/structured-data/intro-structured-data)).
- In a 2019 UK survey, 69% of disabled online shoppers said they click away from sites they find difficult to use ([Click-Away Pound](https://www.clickawaypound.com/downloads/CAP2019PR2.pdf)).

## Can anyone tell you how much your store will grow?

No, and you should be wary of anyone who does. Every number in this guide comes from a specific company, at a specific time, with its own traffic and starting point. A site that loads in 8 seconds has more to gain from speed work than one that loads in 2. A store whose product pages already show prices and ratings in search results has less to gain from structured data than one that shows nothing.

What the published studies do show is direction and order of magnitude: when large sites removed these problems and measured carefully, the effects on sales and engagement were positive and sometimes large. They are evidence that the work can pay off, not a forecast for your store.

## What happened when sites made their pages faster?

These are the best-documented results, with how each was measured. The A/B tests are the strongest evidence, because the only difference between the two versions was the speed work.

| Company | What changed | Result | How it was measured |
|---|---|---|---|
| Vodafone (Italy) | LCP 31% faster on a landing page (5.7 s vs 8.3 s) | 8% more sales, 15% better lead-to-visit rate, 11% better cart-to-visit rate | A/B test, traffic split 50/50 ([web.dev](https://web.dev/case-studies/vodafone)) |
| Rakuten 24 | Core Web Vitals optimization, including a 92.72% better CLS | Revenue per visitor +53.37%, conversion rate +33.13%, average order value +15.20%, exit rate −35.12% | A/B test over one month ([web.dev](https://web.dev/case-studies/rakuten)) |
| Agrofy | LCP 70% faster, CLS 72% better | Load abandonment on product pages fell from 3.8% to 0.9% | Before and after ([web.dev](https://web.dev/case-studies/agrofy)) |
| Yahoo! JAPAN News | CLS reduced by about 0.2 | 15.1% more page views per session, 13.3% longer sessions | Before and after ([web.dev](https://web.dev/case-studies/yahoo-japan-news)) |
| 37 retail, travel, luxury and lead-generation brands | 0.1 s faster across four speed metrics on every page of the journey | Retail conversions +8.4%, travel conversions +10.1% | Correlational analysis of 30 million sessions, commissioned by Google ([web.dev](https://web.dev/case-studies/milliseconds-make-millions)) |

Two cautions apply. These case studies are published by Google's web.dev, which promotes Core Web Vitals, and companies tend to publish their successes, not their failures. And the Deloitte study is correlational: it found that faster sites converted better, which is consistent with speed causing the improvement but doesn't prove it.

Still, the A/B tests are hard to explain away. In both Vodafone's and Rakuten 24's tests, visitors were split at random between two versions that differed only in speed, and the faster version sold more.

## Does faster loading also help in Google Search?

A little, and indirectly. Google says Core Web Vitals are used by its ranking systems and recommends good scores, but also that it shows the most relevant content even when the page experience is poor ([Google Search Central](https://developers.google.com/search/docs/appearance/core-web-vitals)). Speed is a tie-breaker, not a substitute for content people want.

The bigger effect of speed is on what visitors do after they arrive, which is what the A/B tests above measured.

## What did structured data and rich results do for traffic?

Rich results, such as product prices, ratings and breadcrumbs shown in search results, make a listing larger and more informative. Google publishes these results from companies that added structured data ([Google Search Central](https://developers.google.com/search/docs/appearance/structured-data/intro-structured-data)):

- Rotten Tomatoes added structured data to 100,000 pages and measured a 25% higher click-through rate on those pages.
- Food Network converted 80% of its pages to enable search features and saw 35% more visits.
- Nestlé measured an 82% higher click-through rate for pages shown as rich results than for those that weren't.
- Rakuten found that users spent 1.5 times as long on pages with structured data.

The same caution applies: these are Google's examples, and valid markup only makes a page eligible for rich results; Google doesn't guarantee them ([Google Search Central](https://developers.google.com/search/docs/appearance/structured-data/sd-policies)). Some rich results have also been retired: Google stopped showing FAQ rich results on 7 May 2026 ([Google Search Central](https://developers.google.com/search/updates)), so FAQ markup no longer earns extra space.

For a store, the markup that matters most is Product data with price and availability, and breadcrumbs. Our [structured data checker](/structured-data-checker) shows which items on a page are missing the properties Google requires.

## What does accessibility mean for sales?

The business case for accessibility rests on how many people it affects and how they behave when a site doesn't work for them:

- The World Health Organization estimates that 1.3 billion people, about one in six, experience significant disability ([WHO](https://www.who.int/news-room/fact-sheets/detail/disability-and-health)).
- In the 2019 Click-Away Pound survey of UK shoppers with access needs, 69% said they click away from sites they find difficult to use, and the researchers estimated the spending power of those shoppers at £17.1 billion ([Click-Away Pound](https://www.clickawaypound.com/downloads/CAP2019PR2.pdf)). That figure is spending power, not a measured loss.
- Most sites still have the basic problems: WebAIM found detectable WCAG failures on 95.9% of the top one million home pages in 2026, an average of 56.1 errors per page ([WebAIM](https://webaim.org/projects/million/)).

There is no published A/B test that isolates the sales effect of accessibility fixes the way the speed studies do, so we won't quote one. What can be said is that the most common failures, such as low-contrast text, images without alt text, unlabeled form fields and buttons without names, block real customers from reading prices, choosing options and checking out.

Accessibility also carries legal risk in some markets, from ADA demand letters in the US to the European Accessibility Act for stores selling to EU consumers. Our guides on [ADA demand letters](/blog/ada-website-demand-letter) and the [European Accessibility Act](/blog/european-accessibility-act-online-stores) explain the context; they aren't legal advice.

## How can you estimate the effect on your own store?

Use your own numbers and a range of outcomes instead of a single promise. The arithmetic is simple:

**monthly revenue = sessions × conversion rate × average order value**

For example, a store with 20,000 sessions a month, a 1.5% conversion rate and a €60 average order makes 20,000 × 0.015 × €60 = €18,000 a month. If fixes raised the conversion rate by 2% in relative terms (from 1.5% to 1.53%), that would be about €360 more a month; at 5%, about €900; at 10%, about €1,800.

These figures are an illustration of the arithmetic, not a forecast. Which end of the range is realistic depends on how slow and how broken the site is today: the companies in the studies above started from slow pages and fixed specific, measured problems.

Put your own figures from Shopify Analytics or Google Analytics into the formula, then compare the result with what the work costs.

## How do you measure whether the fixes worked?

Measure before you change anything, change one thing at a time where you can, and give real-user data time to update:

1. **Record a baseline.** Note the conversion rate, revenue per session and bounce or exit rate for the four weeks before the change, and your Core Web Vitals in Search Console or PageSpeed Insights.
2. **Make the change and note the date.** If you can, run an A/B test, as Vodafone and Rakuten 24 did; most stores can't, so a dated before-and-after comparison is the practical option.
3. **Wait at least four weeks.** Chrome's real-user data is a rolling 28-day window, so field Core Web Vitals catch up slowly ([Chrome for Developers](https://developer.chrome.com/docs/crux/methodology)).
4. **Compare like with like.** Compare the same weeks year on year if your sales are seasonal, and watch for other changes, such as campaigns or price changes, that happened at the same time.
5. **Re-test the pages.** Run the same scan again to confirm the problems you fixed are gone.

## Where should you start?

Start where the problem is worst and the fix is cheapest. A sensible order is usually:

1. **Anything that stops pages being found**: a leftover noindex tag, robots.txt blocking the site, or a broken sitemap. Our [free SEO checker](/website-seo-checker) finds these.
2. **The main image and scripts on product and home pages**: lazy-loaded hero images, huge images and leftover app scripts cause most slow LCP results. The [speed test](/website-speed-test) measures a page as a throttled phone.
3. **Barriers in the buying path**: low-contrast prices, unlabeled fields and unnamed buttons. The [accessibility checker](/website-accessibility-checker) lists them with the elements and pages.
4. **Product structured data**: so product pages are eligible for price and availability in search results.

The [free website audit](/website-audit) runs all of these at once on up to five key pages and shows the most important finding in each area.

## Frequently asked questions

### Will fixing my Core Web Vitals increase my sales?

Nobody can promise that for a particular store. Controlled A/B tests at Vodafone and Rakuten 24 found more sales from faster pages, and a large correlational study found faster sites converted better. How much your store gains depends on how slow it is today.

### How long until I see results?

Visitors get the faster pages immediately, so conversion changes can show up within weeks. Real-user Core Web Vitals take about 28 days to fully reflect a change, and Google has to recrawl pages before search changes appear.

### Are these case studies reliable?

The A/B tests are the strongest: visitors were split at random and only the speed differed. The others are before-and-after comparisons or correlations. Most are published by Google, which promotes this work, and companies publish their successes more often than their failures.

### Is accessibility worth fixing if nobody has complained?

Few people complain: in the 2019 Click-Away Pound survey, most disabled shoppers who hit a barrier simply left. Fixing the most common failures also tends to improve the site for everyone, for example through clearer contrast and properly labeled forms.

### Does FixReports guarantee more traffic or sales?

No. Our reports find specific, measured problems and explain how to fix them. Whether fixing them increases your traffic or sales depends on your site, your market and how the fixes are made.

## Sources

- web.dev: [How Vodafone found a 31% improvement in LCP increased sales by 8%](https://web.dev/case-studies/vodafone)
- web.dev: [How Rakuten 24's investment in Core Web Vitals increased revenue per visitor by 53.37% and conversion rate by 33.13%](https://web.dev/case-studies/rakuten)
- web.dev: [Agrofy: a 70% improvement in LCP correlated to a 76% reduction in load abandonment](https://web.dev/case-studies/agrofy)
- web.dev: [How CLS optimizations increased Yahoo! JAPAN News's page views per session by 15%](https://web.dev/case-studies/yahoo-japan-news)
- web.dev: [Milliseconds make millions](https://web.dev/case-studies/milliseconds-make-millions)
- Google Search Central: [Introduction to structured data markup](https://developers.google.com/search/docs/appearance/structured-data/intro-structured-data)
- Google Search Central: [General structured data guidelines](https://developers.google.com/search/docs/appearance/structured-data/sd-policies)
- Google Search Central: [Understanding Core Web Vitals and Google search results](https://developers.google.com/search/docs/appearance/core-web-vitals)
- World Health Organization: [Disability fact sheet](https://www.who.int/news-room/fact-sheets/detail/disability-and-health)
- Click-Away Pound: [2019 survey press release](https://www.clickawaypound.com/downloads/CAP2019PR2.pdf)
- WebAIM: [The WebAIM Million (2026)](https://webaim.org/projects/million/)
- Chrome for Developers: [CrUX methodology](https://developer.chrome.com/docs/crux/methodology)