C — https://ourworldindata.org

Site Health

Score: 76 / 100

Based on 8 categories, 0 sections

Your load time meets Google's 'Good' threshold — fine-tuning can still help.

Several missing protections leave your users and data exposed.

Several issues make your site difficult for assistive technology users.

Well-optimized for search — your content is discoverable.

Solid infrastructure — fast server responses across the board.

Mostly compliant — a few items need attention.

Good content signals with minor gaps.

Reasonable footprint with room for optimization.

How is this calculated?

The overall score is a weighted average of individual category scores. Categories with more impact on user experience and security carry more weight.

Performance 25%Security 25%Accessibility 15%SEO 10%Infrastructure 10%Compliance 8%Content 5%Sustainability 2%

Weights reflect general web best practices. Individual needs may differ.

How the composite score is calculated

How you compare

Bootstrap · 823 peers

You 76

Avg 73

At average

0 50 100

Better than 74% of Bootstrap sites See full Bootstrap benchmark →

core-js · 1488 peers

You 76

Avg 72

At average

0 50 100

Better than 84% of core-js sites See full core-js benchmark →

Top Priorities (5)

Content-Security-Policy header is missing

Security gaps expose your site and users to attacks, eroding trust.

Security › Security Headers

No Content-Security-Policy header found

Security gaps expose your site and users to attacks, eroding trust.

Security › Content Security Policy

10 image(s) missing alt attribute

Accessibility issues exclude users with disabilities — up to 15% of your potential audience.

Accessibility › Alt Text Quality

2 image-in-link without alt text

Accessibility issues exclude users with disabilities — up to 15% of your potential audience.

Accessibility › Alt Text Quality

2 image-only link(s) without alt text

Accessibility issues exclude users with disabilities — up to 15% of your potential audience.

Accessibility › Link & Button Quality

View fix priority matrix

Fix Priority Matrix

5 findings

Impact

Quick Wins

High impact, low effort — start here.

Strategic

High impact, requires investment.

Easy Improvements

Small gains, minimal effort.

Nothing in this quadrant — good news.

Deprioritize

Low impact, high effort — do last.

Nothing in this quadrant — good news.

← Low effort High effort →

Embed this badge

Markdown

[![BeaverCheck](https://beavercheck.com/badge?url=https%3A%2F%2Fourworldindata.org)](https://beavercheck.com/results/92ac4322-ab1d-4190-8c90-6104b49eb107)

HTML

<a href="https://beavercheck.com/results/92ac4322-ab1d-4190-8c90-6104b49eb107"><img src="https://beavercheck.com/badge?url=https%3A%2F%2Fourworldindata.org" alt="BeaverCheck Score"></a>

Image URL

https://beavercheck.com/badge?url=https%3A%2F%2Fourworldindata.org

This badge auto-updates with your latest scan result.

What fixing these means

Your site performs reasonably well, but a few targeted fixes could meaningfully improve results. Accessibility issues exclude users who rely on assistive technology — an estimated 15% of your potential audience. Addressing the critical issues below would have the most immediate impact on your user trust.

2 security gaps detected — browsers may warn visitors about your site.

3 accessibility issues exclude users who rely on assistive technology.

Conversion Barriers

1 critical 6 warning

7 barrier(s) likely increasing bounce by ~17%.

Speed (1)

Page feels frozen for 1.3s

+5% bounce

Clicks on the primary CTA are ignored while JavaScript runs

Fix: Break up long tasks; defer non-critical JavaScript to post-hydration

Trust (2)

No HSTS header

+1% bounce

Returning visitors are briefly exposed to downgrade attacks on first request

Fix: Set Strict-Transport-Security: max-age=31536000; includeSubDomains

No Content-Security-Policy header

+1% bounce

Higher XSS blast radius — one compromised script can exfiltrate the checkout form

Fix: Ship a reporting-only CSP first, then enforce once violations are clean

Content (1)

No structured data

+2% bounce

No rich-result eligibility in Google — lower SERP CTR vs competitors with stars and prices

Fix: Add JSON-LD for your page type (Product, Article, FAQPage, LocalBusiness, …)

Navigation (3)

8 link(s) with generic text ("click here", "read more")

+1% bounce

Screen-reader users navigating by link list see no context — and search engines can't infer relevance

Fix: Rewrite with descriptive phrases that identify the destination

No skip-to-content link

+1% bounce

Keyboard and screen-reader users must tab through the entire header on every page

Fix: Add a visible-on-focus <a href="#main">Skip to content</a> as the first focusable element

1 broken link(s) on the page

+2% bounce

Clicks land on 404s — trust drops and the session often ends

Fix: Fix or remove the broken destinations surfaced on the Content tab

Preliminary CRO audit — each barrier links to the tab with detailed analysis.

Return on Investment

€468 investment → €0.67/month returns + EUR 500,000 risk avoided

Payback period: > 2 years First-year ROI: -98%

Investment

€468

6h · 5 findings

Monthly returns

€0.67 /mo

~€8.03 / year

Bandwidth savings €0.67

Regulatory risk avoided

EUR 500,000

if kept compliant

EAA EUR 500,000

€85 — in quick wins — start here for the fastest payback

Figures combine localized regulatory fine ceilings, search/conversion value priced against local CPC, and bandwidth waste estimates. Results depend on implementation quality and audience composition. Not legal or financial advice.

Full methodology & sources

Estimated Remediation Cost

€468

5.5 developer hours at €85/hr

Based on European Union rates (€85/hr)

Quick wins

€85 2 fixes in ~60 minutes

Start here for the best return on investment

Cost by category

Cost by effort level

Adjust assumptions

Custom rate

€ /hr

Rates reflect fully-loaded developer cost including overhead

How developer rates are sourced

What Inaction Is Costing You

€41,667 / month at risk

~€500,008 / year if left unfixed

Compliance Risk

€500,000

EAA

No <main> landmark found
EAA: EUR 1,000 – EUR 500,000
Skip navigation link is missing (WCAG 2.4.1)
EAA: EUR 1,000 – EUR 500,000
No H1 heading found
EAA: EUR 1,000 – EUR 500,000

+4 more

Bandwidth Waste

€0.67 /mo

9033.9 MB/mo × 0.074 EUR/GB

Optimize transfer: save ~903 KB per page load
Saves €0.67/mo

Compliance figures represent the statutory maximum fine for the most severe triggered category, capped per regulation — not the sum of per-finding penalties. Based on published regulatory fine ranges. This is not legal advice.

Compliance methodology · SEO assumptions · Bandwidth model

Your performance is already good — improvements may show diminishing returns

Monthly visitors

Unique monthly visitors from your analytics

Conversion rate (%)

Purchases, signups, or key actions

Avg. order value

Optional — for revenue estimation

additional conversions/month

more engaged visitors from reduced bounce

potential monthly revenue

Current bounce (est.)

After fixes (est.)

Estimated bounce reduction

Fix 5 critical issues to capture this value

How this is calculated

Based on Google/Deloitte research ("Milliseconds Make Millions") showing a ~7% bounce rate increase per additional second of LCP above the 2.5s "Good" threshold.

Your site's LCP: → estimated after fixes.

These are estimates based on industry research — actual results vary

Bounce-rate model & assumptions

Your data stays in your browser — nothing is sent to our servers

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Lighthouse Scores

Industry-standard audits powered by Google Lighthouse.

Performance

Accessibility

Best Practices

SEO

Core Web Vitals

Key metrics that affect user experience.

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

1.09 s

Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.

1.75 s

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

1.25 s

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.039

Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.

2.87 s

Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.

10.75 s

Detailed Report

Audit breakdown by category with detailed findings.

Performance

Insights

Remove large, duplicate JavaScript modules from bundles to reduce unnecessary bytes consumed by network activity.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Polyfills and transforms enable older browsers to use new JavaScript features. However, many aren't necessary for modern browsers. Consider modifying your JavaScript build process to not transpile Baseline features, unless you know you must support older browsers. Learn why most sites can deploy ES6+ code without transpiling

Why this matters

Shipping ES5 transpiled code to modern browsers wastes bytes — every user with an evergreen browser pays for compatibility you don't need.

Learn more ▾

Most users today run browsers that natively support ES6+, async/await, optional chaining, and the rest of modern JavaScript. Transpiling to ES5 'just in case' adds 20-40% to your bundle for no benefit. Configure your build to target a modern browserslist, or ship a differential bundle pair (modern + legacy) with the module/nomodule pattern.

Source: Google web.dev / Lighthouse

3rd party code can significantly impact load performance. Reduce and defer loading of 3rd party code to prioritize your page's content.

Why this matters

Performance issues directly impact user engagement and conversion rates.

A forced reflow occurs when JavaScript queries geometric properties (such as offsetWidth) after styles have been invalidated by a change to the DOM state. This can result in poor performance. Learn more about forced reflows and possible mitigations.

Why this matters

Performance issues directly impact user engagement and conversion rates.

headings: [map[key:source label:Source valueType:source-location] map[granularity:1 key:reflowTime label:Total reflow time valueType:ms]]

items: [map[reflowTime:33.212 source:map[type:text value:[unattributed]]]]

Optimize LCP by making the LCP image discoverable from the HTML immediately, and avoiding lazy-loading

Why this matters

Performance issues directly impact user engagement and conversion rates.

lhId: page-0-DIV

nodeLabel: Research and data to make progress against the world’s largest problems.Read ab…

path: 1,DIV

selector: div.grid > div.article-block__homepage-search

snippet: <div class="article-block__homepage-search grid grid-cols-12-full-width span-cols-14">

A long cache lifetime can speed up repeat visits to your page. Learn more about caching.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Request	Cache TTL	Transfer Size
/grapher/share-of-population-in-extreme-poverty.png?imWid...	3600.0 s	144.4 KiB
ourworldindata.org/grapher/mobile-cellular-subscriptions-per-100-people.png	3600.0 s	132.4 KiB
ourworldindata.org/grapher/child-mortality.png?time=earliest..latest&imWidth=850	3600.0 s	83.9 KiB
ourworldindata.org/explorers/climate-change.png	0.0 ms	62.3 KiB
ourworldindata.org/grapher/life-expectancy.png?imWidth=850	3600.0 s	73.8 KiB
/grapher/co-emissions-per-capita.png?tab=chart&country=US...	3600.0 s	71.8 KiB
/explorers/co2.png?facet=none&country=CHN~USA~IND~FRA&Gas...	0.0 ms	55.7 KiB
/grapher/technology-adoption-by-households-in-the-united-...	3600.0 s	63.2 KiB
/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/817073af-ee...	172800.0 s	90.3 KiB
/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/8a2c84fa-1d...	172800.0 s	80.1 KiB
/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/92713fbe-c3...	172800.0 s	76.2 KiB
/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/2b579c45-b1...	172800.0 s	67.6 KiB
/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/23d16973-25...	172800.0 s	66.1 KiB
/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/e3b40748-b3...	172800.0 s	56.3 KiB
/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/014e8530-1d...	172800.0 s	35.8 KiB
static.cloudflareinsights.com/beacon.min.js	86400.0 s	10.7 KiB
/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/e8c1792e-59...	172800.0 s	3.8 KiB
/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/b18a3db6-93...	172800.0 s	3.5 KiB
/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/c0176bc5-b9...	172800.0 s	1.7 KiB

Reducing the download time of images can improve the perceived load time of the page and LCP. Learn more about optimizing image size

Why this matters

Performance issues directly impact user engagement and conversion rates.

	URL	Resource Size	Est Savings
Line chart of the share of total electricity generation from nuclear power wher… `a.latest-data-insights__card__data-insight > div.image > picture > img`	/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/817073af-ee...	89.9 KiB	56.1 KiB
Line chart of estimated annual suicide deaths per 100,000 people from 1980 to 2… `a.latest-data-insights__card__data-insight > div.image > picture > img`	/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/8a2c84fa-1d...	79.7 KiB	49.7 KiB
Slope chart of the share of the population that is undernourished where regiona… `a.latest-data-insights__card__data-insight > div.image > picture > img`	/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/92713fbe-c3...	75.8 KiB	47.3 KiB
Line chart of reported cervical cancer deaths per 100,000 women in the United K… `a.latest-data-insights__card__data-insight > div.image > picture > img`	/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/2b579c45-b1...	67.2 KiB	41.9 KiB
Small multiple line charts of mobile and landline phone subscriptions per 100 p… `a.latest-data-insights__card__data-insight > div.image > picture > img`	/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/23d16973-25...	65.7 KiB	41.0 KiB
Stacked area chart of annual premature deaths from household indoor air polluti… `a.latest-data-insights__card__data-insight > div.image > picture > img`	/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/e3b40748-b3...	55.9 KiB	34.9 KiB
div.GrapherWithFallback > figure.grapherPreview > picture > img.GrapherImage `div.GrapherWithFallback > figure.grapherPreview > picture > img.GrapherImage`	ourworldindata.org/grapher/child-mortality.png?time=earliest..latest&imWidth=850	83.4 KiB	28.8 KiB
featured image `a.homepage-intro__featured-tile > div.image > picture > img`	/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/014e8530-1d...	35.4 KiB	24.6 KiB

These insights are also available in the Chrome DevTools Performance Panel - record a trace to view more detailed information.

The maximum potential First Input Delay that your users could experience is the duration of the longest task. Learn more about the Maximum Potential First Input Delay metric.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Time to Interactive is the amount of time it takes for the page to become fully interactive. Learn more about the Time to Interactive metric.

Why this matters

Performance issues directly impact user engagement and conversion rates.

TTI

Diagnostics

Consider reducing the time spent parsing, compiling, and executing JS. You may find delivering smaller JS payloads helps with this. Learn how to reduce Javascript execution time.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL	Total CPU Time	Script Evaluation	Script Parse
Unattributable	1.5 s	576 ms	0.0 ms
ourworldindata.org/assets/owid.mjs	932 ms	708 ms	12 ms
ourworldindata.org/	687 ms	15 ms	19 ms
www.googletagmanager.com/gtm.js?id=GTM-N2D4V8S	215 ms	174 ms	39 ms
www.googletagmanager.com/gtag/js?id=G-RSY8NMC3MT&cx=c&gtm=4e64h1	175 ms	143 ms	31 ms

Consider reducing the time spent parsing, compiling and executing JS. You may find delivering smaller JS payloads helps with this. Learn how to minimize main-thread work

Why this matters

Performance issues directly impact user engagement and conversion rates.

Category	Time Spent
Script Evaluation	1.6 s
Other	1.0 s
Style & Layout	517 ms
Rendering	125 ms
Script Parsing & Compilation	104 ms
Garbage Collection	102 ms
Parse HTML & CSS	57 ms

Reduce unused JavaScript and defer loading scripts until they are required to decrease bytes consumed by network activity. Learn how to reduce unused JavaScript.

Why this matters

Multi-megabyte JavaScript bundles delay every interactive feature on the page.

Learn more ▾

This is the Lighthouse audit fired when too much JS is shipped relative to what executes. The fix isn't a config flag — it requires bundle analysis (webpack-bundle-analyzer, rollup-plugin-visualizer), splitting routes into chunks, lazy-loading off-screen components, and removing unused dependencies. Fundamentally different from minification: minifying reduces byte count, this reduces what's downloaded at all.

Source: Google web.dev / Lighthouse

Estimated savings: 0.0 ms 709.3 KiB

URL	Transfer Size	Est Savings
ourworldindata.org/assets/owid.mjs	986.6 KiB	585.0 KiB
www.googletagmanager.com/gtag/js?id=G-RSY8NMC3MT&cx=c&gtm=4e64h1	152.1 KiB	64.1 KiB
www.googletagmanager.com/gtm.js?id=GTM-N2D4V8S	130.1 KiB	60.2 KiB

Large network payloads cost users real money and are highly correlated with long load times. Learn how to reduce payload sizes.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL	Transfer Size
ourworldindata.org/assets/owid.mjs	988.0 KiB
www.googletagmanager.com/gtag/js?id=G-RSY8NMC3MT&cx=c&gtm=4e64h1	152.2 KiB
/grapher/share-of-population-in-extreme-poverty.png?imWid...	144.4 KiB
ourworldindata.org/grapher/mobile-cellular-subscriptions-per-100-people.png	132.4 KiB
www.googletagmanager.com/gtm.js?id=GTM-N2D4V8S	130.5 KiB
ourworldindata.org/dods.json	95.7 KiB
/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/817073af-ee...	90.3 KiB
ourworldindata.org/grapher/child-mortality.png?time=earliest..latest&imWidth=850	83.9 KiB
/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/8a2c84fa-1d...	80.1 KiB
/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/92713fbe-c3...	76.2 KiB

More information about the performance of your application. These numbers don't directly affect the Performance score.

●Layout shift culprits

●Document request latency

●Optimize DOM size

●Font display

●LCP breakdown

●Modern HTTP

●Network dependency tree

●Render blocking requests

●Optimize viewport for mobile

●Minify CSS

●Minify JavaScript

●Reduce unused CSS

●User Timing marks and measures 8 user timings

●Avoid long main-thread tasks 6 long tasks found

●Image elements have explicit `width` and `height`

●Page didn't prevent back/forward cache restoration

●Network Requests

●Network Round Trip Times 20 ms

●Server Backend Latencies 40 ms

●Tasks

●Diagnostics

●Metrics

●Screenshot Thumbnails

●Final Screenshot

●Script Treemap Data

●Resources Summary

●Avoid multiple page redirects

●Initial server response time was short Root document took 20 ms

●Avoid large layout shifts 2 layout shifts found

○INP breakdown

○Avoid non-composited animations

Accessibility

These checks highlight opportunities to improve the accessibility of your web app. Automatic detection can only detect a subset of issues and does not guarantee the accessibility of your web app, so manual testing is also encouraged.

Contrast

Low-contrast text is difficult or impossible for many users to read. Learn how to provide sufficient color contrast.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
Try “Life expectancy”, “Poverty Nigeria Vietnam”, “CO2 France”… `div#autocomplete > div.aa-Autocomplete > button#autocomplete-1-label > div.aa-DetachedSearchButtonPlaceholder`
NEW `div.homepage-intro__featured-work-column > a.homepage-intro__featured-tile > span.h6-black-caps > span.homepage-intro__new-tag`
TODAY `li.latest-data-insights__card > a.latest-data-insights__card__data-insight > div.latest-data-insights__card-right > p.data-insight-dateline`
APRIL 18 `li.latest-data-insights__card > a.latest-data-insights__card__data-insight > div.latest-data-insights__card-right > p.data-insight-dateline`
Death rates for cervical cancer in the United Kingdom have fallen by 80% since … `li.latest-data-insights__card > a.latest-data-insights__card__data-insight > div.latest-data-insights__card-right > h3#latest-data-insights__card-title-1`
FOLLOW US `footer.site-footer > div.footer-base > div.footer-base__socials > h5.h5-black-caps`

Low-contrast text is difficult or impossible for many users to read. Link text that is discernible improves the experience for users with low vision. Learn how to make links distinguishable.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
Global Change Data Lab `footer.site-footer > div.footer-left > p.body-3-medium > a`
CC BY `footer.site-footer > div.footer-left > p.body-3-medium > a`
MIT license `footer.site-footer > div.footer-left > p.body-3-medium > a`
FAQs `footer.site-footer > div.footer-left > p.body-3-medium > a`

These are opportunities to improve the legibility of your content.

Navigation

Properly ordered headings that do not skip levels convey the semantic structure of the page, making it easier to navigate and understand when using assistive technologies. Learn more about heading order.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
What share of children die before their fifth birthday? `div > div.key-indicator > div.left > h4.narrative-title`
Our World in Data is free and accessible for everyone. `section.donate-footer > div.donate-footer-inner > div > h4`

These are opportunities to improve keyboard navigation in your application.

Names and labels

Informative elements should aim for short, descriptive alternate text. Decorative elements can be ignored with an empty alt attribute. Learn more about the `alt` attribute.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
a.homepage-intro__featured-tile > div.image > picture > img `a.homepage-intro__featured-tile > div.image > picture > img`
div.GrapherWithFallback > figure.grapherPreview > picture > img.GrapherImage `div.GrapherWithFallback > figure.grapherPreview > picture > img.GrapherImage`

Link text (and alternate text for images, when used as links) that is discernible, unique, and focusable improves the navigation experience for screen reader users. Learn how to make links accessible.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
footer.site-footer > div.footer-base > div.footer-base__socials > a `footer.site-footer > div.footer-base > div.footer-base__socials > a`
footer.site-footer > div.footer-base > div.footer-base__socials > a `footer.site-footer > div.footer-base > div.footer-base__socials > a`
footer.site-footer > div.footer-base > div.footer-base__socials > a `footer.site-footer > div.footer-base > div.footer-base__socials > a`
footer.site-footer > div.footer-base > div.footer-base__socials > a `footer.site-footer > div.footer-base > div.footer-base__socials > a`
footer.site-footer > div.footer-base > div.footer-base__socials > a `footer.site-footer > div.footer-base > div.footer-base__socials > a`
footer.site-footer > div.footer-base > div.footer-base__socials > a `footer.site-footer > div.footer-base > div.footer-base__socials > a`
footer.site-footer > div.footer-base > div.footer-base__socials > a `footer.site-footer > div.footer-base > div.footer-base__socials > a`
footer.site-footer > div.footer-base > div.footer-base__socials > a `footer.site-footer > div.footer-base > div.footer-base__socials > a`

These are opportunities to improve the semantics of the controls in your application. This may enhance the experience for users of assistive technology, like a screen reader.

Best practices

One main landmark helps screen reader users navigate a web page. Learn more about landmarks.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
html.js-enabled `html.js-enabled`

These items highlight common accessibility best practices.

Visible text labels that do not match the accessible name can result in a confusing experience for screen reader users. Learn more about accessible names.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
NEW ARTICLE · 6 MIN READ Most people care about farm animals — our food system … `section.homepage-intro > div.homepage-intro__featured-work > div.homepage-intro__featured-work-column > a.homepage-intro__featured-tile`
FROM OUR CLASSICS How many species are there? How many species do we share our… `section.homepage-intro > div.homepage-intro__featured-work > div.homepage-intro__featured-work-column > a.homepage-intro__featured-tile`
ANNOUNCEMENT We’re looking for a writer We’re hiring a writer who can make the… `section.homepage-intro > div.homepage-intro__featured-work > div.homepage-intro__featured-work-column > a.homepage-intro__featured-tile`
ARTICLE · 6 MIN READ What do people die from in different countries? Explore c… `section.homepage-intro > div.homepage-intro__featured-work > div.homepage-intro__featured-work-column > a.homepage-intro__featured-tile`
DATA UPDATE - YESTERDAY NVIDIA's data center & AI revenue has grown nearly 15-f… `div.homepage-intro__announcements > ul.homepage-intro__announcements-list > li.homepage-intro__announcement > a.homepage-intro__announcement-link`
DATA UPDATE - THIS WEEK Billions of people depend on synthetic fertilizers. Tra… `div.homepage-intro__announcements > ul.homepage-intro__announcements-list > li.homepage-intro__announcement > a.homepage-intro__announcement-link`
TODAY Indoor air pollution causes almost three million premature deaths every … `div.latest-data-insights__viewport > ul.latest-data-insights__card-container > li.latest-data-insights__card > a.latest-data-insights__card__data-insight`
APRIL 18 Death rates for cervical cancer in the United Kingdom have fallen by … `div.latest-data-insights__viewport > ul.latest-data-insights__card-container > li.latest-data-insights__card > a.latest-data-insights__card__data-insight`

○Interactive controls are keyboard focusable

○Interactive elements indicate their purpose and state

○The page has a logical tab order

○Visual order on the page follows DOM order

○User focus is not accidentally trapped in a region

○The user's focus is directed to new content added to the page

○HTML5 landmark elements are used to improve navigation

○Offscreen content is hidden from assistive technology

○Custom controls have associated labels

○Custom controls have ARIA roles

●`[aria-*]` attributes match their roles

●`[aria-hidden="true"]` is not present on the document `<body>`

●`[role]`s have all required `[aria-*]` attributes

●`[role]` values are valid

●`[aria-*]` attributes have valid values

●`[aria-*]` attributes are valid and not misspelled

●Buttons have an accessible name

●`[user-scalable="no"]` is not used in the `<meta name="viewport">` element and the `[maximum-scale]` attribute is not less than 5.

●ARIA attributes are used as specified for the element's role

●`[aria-hidden="true"]` elements do not contain focusable descendents

●ARIA input fields have accessible names

●Elements use only permitted ARIA attributes

●Document has a `<title>` element

●`<html>` element has a `[lang]` attribute

●`<html>` element has a valid value for its `[lang]` attribute

●Lists contain only `<li>` elements and script supporting elements (`<script>` and `<template>`).

●List items (`<li>`) are contained within `<ul>`, `<ol>` or `<menu>` parent elements

●No element has a `[tabindex]` value greater than 0

●Touch targets have sufficient size and spacing.

●Deprecated ARIA roles were not used

●ARIA IDs are unique

○`[accesskey]` values are unique

○`button`, `link`, and `menuitem` elements have accessible names

○Elements with `role="dialog"` or `role="alertdialog"` have accessible names.

○ARIA `meter` elements have accessible names

○ARIA `progressbar` elements have accessible names

○Elements with an ARIA `[role]` that require children to contain a specific `[role]` have all required children.

○`[role]`s are contained by their required parent element

○Elements with the `role=text` attribute do not have focusable descendents.

○ARIA toggle fields have accessible names

○ARIA `tooltip` elements have accessible names

○ARIA `treeitem` elements have accessible names

○The page contains a heading, skip link, or landmark region

○`<dl>`'s contain only properly-ordered `<dt>` and `<dd>` groups, `<script>`, `<template>` or `<div>` elements.

○Definition list items are wrapped in `<dl>` elements

○No form fields have multiple labels

○`<frame>` or `<iframe>` elements have a title

○`<html>` element has an `[xml:lang]` attribute with the same base language as the `[lang]` attribute.

○Input buttons have discernible text.

○`<input type="image">` elements have `[alt]` text

○Form elements have associated labels

○The document does not use `<meta http-equiv="refresh">`

○`<object>` elements have alternate text

○Select elements have associated label elements.

○Skip links are focusable.

○Cells in a `<table>` element that use the `[headers]` attribute refer to table cells within the same table.

○`<th>` elements and elements with `[role="columnheader"/"rowheader"]` have data cells they describe.

○`[lang]` attributes have a valid value

○`<video>` elements contain a `<track>` element with `[kind="captions"]`

○Tables have different content in the summary attribute and `<caption>`.

○All heading elements contain content.

○Uses ARIA roles only on compatible elements

○Image elements do not have `[alt]` attributes that are redundant text.

○Identical links have the same purpose.

○Tables use `<caption>` instead of cells with the `[colspan]` attribute to indicate a caption.

○`<td>` elements in a large `<table>` have one or more table headers.

Best Practices

General

Errors logged to the console indicate unresolved problems. They can come from network request failures and other browser concerns. Learn more about this errors in console diagnostic audit

Why this matters

Performance issues directly impact user engagement and conversion rates.

Source Description

Source	Description
ourworldindata.org/assets/owid.mjs line 33, col 31234	Error: Minified React error #418; visit https://react.dev/errors/418?args[]=HTML&args[]= for the full message or use the non-minified dev environment for full errors and additional helpful warnings. at vi (https://ourworldindata.org/assets/owid.mjs:34:31235) at dc (https://ourworldindata.org/assets/owid.mjs:34:82026) at du (https://ourworldindata.org/assets/owid.mjs:34:116124) at jee (https://ourworldindata.org/assets/owid.mjs:34:115169) at lu (https://ourworldindata.org/assets/owid.mjs:34:115000) at Ql (https://ourworldindata.org/assets/owid.mjs:34:111476) at Vu (https://ourworldindata.org/assets/owid.mjs:34:123493) at MessagePort.D (https://ourworldindata.org/assets/owid.mjs:27:8867)

ourworldindata.org/assets/owid.mjs line 33, col 31234

Error: Minified React error #418; visit https://react.dev/errors/418?args[]=HTML&args[]= for the full message or use the non-minified dev environment for full errors and additional helpful warnings.
    at vi (https://ourworldindata.org/assets/owid.mjs:34:31235)
    at dc (https://ourworldindata.org/assets/owid.mjs:34:82026)
    at du (https://ourworldindata.org/assets/owid.mjs:34:116124)
    at jee (https://ourworldindata.org/assets/owid.mjs:34:115169)
    at lu (https://ourworldindata.org/assets/owid.mjs:34:115000)
    at Ql (https://ourworldindata.org/assets/owid.mjs:34:111476)
    at Vu (https://ourworldindata.org/assets/owid.mjs:34:123493)
    at MessagePort.D (https://ourworldindata.org/assets/owid.mjs:27:8867)

●Uses HTTPS

●Avoids deprecated APIs

●Avoids third-party cookies

●Allows users to paste into input fields

●Avoids requesting the geolocation permission on page load

●Avoids requesting the notification permission on page load

●Displays images with correct aspect ratio

●Serves images with appropriate resolution

●Page has the HTML doctype

●Properly defines charset

●No issues in the `Issues` panel in Chrome Devtools

●Ensure CSP is effective against XSS attacks

●Use a strong HSTS policy

●Ensure proper origin isolation with COOP

●Mitigate clickjacking with XFO or CSP

●Mitigate DOM-based XSS with Trusted Types

●Detected JavaScript libraries

●Page has valid source maps

○Redirects HTTP traffic to HTTPS

SEO

These checks ensure that your page is following basic search engine optimization advice. There are many additional factors Lighthouse does not score here that may affect your search ranking, including performance on Core Web Vitals. Learn more about Google Search Essentials.

Content Best Practices

Informative elements should aim for short, descriptive alternate text. Decorative elements can be ignored with an empty alt attribute. Learn more about the `alt` attribute.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
a.homepage-intro__featured-tile > div.image > picture > img `a.homepage-intro__featured-tile > div.image > picture > img`
div.GrapherWithFallback > figure.grapherPreview > picture > img.GrapherImage `div.GrapherWithFallback > figure.grapherPreview > picture > img.GrapherImage`

Format your HTML in a way that enables crawlers to better understand your app’s content.

○Structured data is valid

●Page isn’t blocked from indexing

●Document has a `<title>` element

●Document has a meta description

●Page has successful HTTP status code

●Links have descriptive text

●Links are crawlable

●robots.txt is valid

●Document has a valid `hreflang`

●Document has a valid `rel=canonical`

Lighthouse Scores

Industry-standard audits powered by Google Lighthouse. — Desktop

Performance

Accessibility

Best Practices

SEO

Core Web Vitals

Key metrics that affect user experience. — Desktop

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

439 ms

Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.

771 ms

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

70 ms

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.002

Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.

1.17 s

Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.

2.91 s

Detailed Report

Audit breakdown by category with detailed findings.

Performance

Insights

Remove large, duplicate JavaScript modules from bundles to reduce unnecessary bytes consumed by network activity.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Why this matters

Shipping ES5 transpiled code to modern browsers wastes bytes — every user with an evergreen browser pays for compatibility you don't need.

Learn more ▾

Source: Google web.dev / Lighthouse

3rd party code can significantly impact load performance. Reduce and defer loading of 3rd party code to prioritize your page's content.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Optimize LCP by making the LCP image discoverable from the HTML immediately, and avoiding lazy-loading

Why this matters

Performance issues directly impact user engagement and conversion rates.

lhId: page-0-DIV

nodeLabel: Research and data to make progress against the world’s largest problems. Read a…

path: 1,HTML,1,BODY,1,DIV,0,DIV,1,DIV

selector: body > div#owid-document-root > div.grid > div.article-block__homepage-search

snippet: <div class="article-block__homepage-search grid grid-cols-12-full-width span-cols-14">

A long cache lifetime can speed up repeat visits to your page. Learn more about caching.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Request	Cache TTL	Transfer Size
/grapher/share-of-population-in-extreme-poverty.png?imWid...	3600.0 s	144.4 KiB
/grapher/gdp-per-capita-maddison-project-database.png?imW...	3600.0 s	136.2 KiB
ourworldindata.org/grapher/mobile-cellular-subscriptions-per-100-people.png	3600.0 s	132.4 KiB
/grapher/share-of-the-population-with-access-to-electrici...	3600.0 s	130.0 KiB
ourworldindata.org/grapher/child-mortality.png?time=earliest..latest&imWidth=850	3600.0 s	83.9 KiB
ourworldindata.org/grapher/prevalence-of-undernourishment.png?imWidth=850	3600.0 s	81.5 KiB
ourworldindata.org/explorers/climate-change.png	0.0 ms	62.3 KiB
ourworldindata.org/grapher/life-expectancy.png?imWidth=850	3600.0 s	73.8 KiB
/grapher/co-emissions-per-capita.png?tab=chart&country=US...	3600.0 s	71.8 KiB
ourworldindata.org/grapher/cross-country-literacy-rates.png?imWidth=850	3600.0 s	70.1 KiB
/explorers/co2.png?facet=none&country=CHN~USA~IND~FRA&Gas...	0.0 ms	55.7 KiB
/grapher/technology-adoption-by-households-in-the-united-...	3600.0 s	63.2 KiB
/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/817073af-ee...	172800.0 s	90.3 KiB
/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/92713fbe-c3...	172800.0 s	76.2 KiB
/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/2b579c45-b1...	172800.0 s	67.6 KiB
/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/e3b40748-b3...	172800.0 s	56.3 KiB
static.cloudflareinsights.com/beacon.min.js	86400.0 s	10.7 KiB
/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/014e8530-1d...	172800.0 s	9.9 KiB
/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/b18a3db6-93...	172800.0 s	2.4 KiB
/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/e8c1792e-59...	172800.0 s	2.3 KiB
/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/c0176bc5-b9...	172800.0 s	1.3 KiB
/a?v=3&t=l&pid=834032224&rv=64h1&tag_exp=0~115938465~1159...	0.0 ms	11 B

Reducing the download time of images can improve the perceived load time of the page and LCP. Learn more about optimizing image size

Why this matters

Performance issues directly impact user engagement and conversion rates.

	URL	Resource Size	Est Savings
Line chart of the share of total electricity generation from nuclear power wher… `a.latest-data-insights__card__data-insight > div.image > picture > img`	/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/817073af-ee...	89.9 KiB	79.5 KiB
Slope chart of the share of the population that is undernourished where regiona… `a.latest-data-insights__card__data-insight > div.image > picture > img`	/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/92713fbe-c3...	75.8 KiB	67.0 KiB
Line chart of reported cervical cancer deaths per 100,000 women in the United K… `a.latest-data-insights__card__data-insight > div.image > picture > img`	/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/2b579c45-b1...	67.2 KiB	59.4 KiB
Stacked area chart of annual premature deaths from household indoor air polluti… `a.latest-data-insights__card__data-insight > div.image > picture > img`	/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/e3b40748-b3...	55.9 KiB	49.4 KiB

These insights are also available in the Chrome DevTools Performance Panel - record a trace to view more detailed information.

The maximum potential First Input Delay that your users could experience is the duration of the longest task. Learn more about the Maximum Potential First Input Delay metric.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Time to Interactive is the amount of time it takes for the page to become fully interactive. Learn more about the Time to Interactive metric.

Why this matters

Performance issues directly impact user engagement and conversion rates.

TTI

Diagnostics

Reduce unused JavaScript and defer loading scripts until they are required to decrease bytes consumed by network activity. Learn how to reduce unused JavaScript.

Why this matters

Multi-megabyte JavaScript bundles delay every interactive feature on the page.

Learn more ▾

Source: Google web.dev / Lighthouse

Estimated savings: 0.0 ms 712.5 KiB

URL	Transfer Size	Est Savings
ourworldindata.org/assets/owid.mjs	986.2 KiB	591.1 KiB
www.googletagmanager.com/gtag/js?id=G-RSY8NMC3MT&cx=c&gtm=4e64h1	152.1 KiB	63.1 KiB
www.googletagmanager.com/gtm.js?id=GTM-N2D4V8S	130.1 KiB	58.3 KiB

Large network payloads cost users real money and are highly correlated with long load times. Learn how to reduce payload sizes.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL	Transfer Size
ourworldindata.org/assets/owid.mjs	987.9 KiB
www.googletagmanager.com/gtag/js?id=G-RSY8NMC3MT&cx=c&gtm=4e64h1	152.2 KiB
/grapher/share-of-population-in-extreme-poverty.png?imWid...	144.4 KiB
/grapher/gdp-per-capita-maddison-project-database.png?imW...	136.2 KiB
ourworldindata.org/grapher/mobile-cellular-subscriptions-per-100-people.png	132.4 KiB
www.googletagmanager.com/gtm.js?id=GTM-N2D4V8S	130.5 KiB
/grapher/share-of-the-population-with-access-to-electrici...	130.0 KiB
ourworldindata.org/dods.json	95.7 KiB
/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/817073af-ee...	90.3 KiB
ourworldindata.org/grapher/child-mortality.png?time=earliest..latest&imWidth=850	83.9 KiB

More information about the performance of your application. These numbers don't directly affect the Performance score.

●Layout shift culprits

●Document request latency

●Optimize DOM size

●Font display

●Forced reflow

●LCP breakdown

●Modern HTTP

●Network dependency tree

●Render blocking requests

●Optimize viewport for mobile

●Minify CSS

●Minify JavaScript

●Reduce unused CSS

●User Timing marks and measures 129 user timings

●JavaScript execution time 0.5 s

●Minimizes main-thread work 0.9 s

●Avoid long main-thread tasks 3 long tasks found

●Image elements have explicit `width` and `height`

●Page didn't prevent back/forward cache restoration

●Network Requests

●Network Round Trip Times 20 ms

●Server Backend Latencies 30 ms

●Tasks

●Diagnostics

●Metrics

●Screenshot Thumbnails

●Final Screenshot

●Script Treemap Data

●Resources Summary

●Avoid multiple page redirects

●Initial server response time was short Root document took 30 ms

●Avoid large layout shifts 2 layout shifts found

○INP breakdown

○Avoid non-composited animations

Accessibility

Contrast

Low-contrast text is difficult or impossible for many users to read. Learn how to provide sufficient color contrast.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
NEW `div.homepage-intro__featured-work-column > a.homepage-intro__featured-tile > span.h6-black-caps > span.homepage-intro__new-tag`
TODAY `li.latest-data-insights__card > a.latest-data-insights__card__data-insight > div.latest-data-insights__card-right > p.data-insight-dateline`
APRIL 18 `li.latest-data-insights__card > a.latest-data-insights__card__data-insight > div.latest-data-insights__card-right > p.data-insight-dateline`
Continue reading `a.latest-data-insights__card__data-insight > div.latest-data-insights__card-right > div.latest-data-insights__card-continue > span.body-3-medium-underlined`

Low-contrast text is difficult or impossible for many users to read. Link text that is discernible improves the experience for users with low vision. Learn how to make links distinguishable.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
Global Change Data Lab `footer.site-footer > div.footer-left > p.body-3-medium > a`
CC BY `footer.site-footer > div.footer-left > p.body-3-medium > a`
MIT license `footer.site-footer > div.footer-left > p.body-3-medium > a`
FAQs `footer.site-footer > div.footer-left > p.body-3-medium > a`

These are opportunities to improve the legibility of your content.

Navigation

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
Our World in Data is free and accessible for everyone. `section.donate-footer > div.donate-footer-inner > div > h4`

These are opportunities to improve keyboard navigation in your application.

Names and labels

Informative elements should aim for short, descriptive alternate text. Decorative elements can be ignored with an empty alt attribute. Learn more about the `alt` attribute.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
a.homepage-intro__featured-tile > div.image > picture > img `a.homepage-intro__featured-tile > div.image > picture > img`
div.GrapherWithFallback > figure.grapherPreview > picture > img.GrapherImage `div.GrapherWithFallback > figure.grapherPreview > picture > img.GrapherImage`

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
footer.site-footer > div.footer-base > div.footer-base__socials > a `footer.site-footer > div.footer-base > div.footer-base__socials > a`
footer.site-footer > div.footer-base > div.footer-base__socials > a `footer.site-footer > div.footer-base > div.footer-base__socials > a`
footer.site-footer > div.footer-base > div.footer-base__socials > a `footer.site-footer > div.footer-base > div.footer-base__socials > a`
footer.site-footer > div.footer-base > div.footer-base__socials > a `footer.site-footer > div.footer-base > div.footer-base__socials > a`
footer.site-footer > div.footer-base > div.footer-base__socials > a `footer.site-footer > div.footer-base > div.footer-base__socials > a`
footer.site-footer > div.footer-base > div.footer-base__socials > a `footer.site-footer > div.footer-base > div.footer-base__socials > a`
footer.site-footer > div.footer-base > div.footer-base__socials > a `footer.site-footer > div.footer-base > div.footer-base__socials > a`
footer.site-footer > div.footer-base > div.footer-base__socials > a `footer.site-footer > div.footer-base > div.footer-base__socials > a`

These are opportunities to improve the semantics of the controls in your application. This may enhance the experience for users of assistive technology, like a screen reader.

Best practices

One main landmark helps screen reader users navigate a web page. Learn more about landmarks.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
html.js-enabled `html.js-enabled`

These items highlight common accessibility best practices.

Visible text labels that do not match the accessible name can result in a confusing experience for screen reader users. Learn more about accessible names.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
Browse by topic `ul > li > div.SiteNavigationToggle > button.SiteNavigationToggle__button`
NEW ARTICLE · 6 MIN READ Most people care about farm animals — our food system … `section.homepage-intro > div.homepage-intro__featured-work > div.homepage-intro__featured-work-column > a.homepage-intro__featured-tile`
ANNOUNCEMENT We’re looking for a writer Hannah Ritchie `section.homepage-intro > div.homepage-intro__featured-work > div.homepage-intro__featured-work-column > a.homepage-intro__featured-tile`
FROM OUR CLASSICS How many species are there? How many species do we share our… `section.homepage-intro > div.homepage-intro__featured-work > div.homepage-intro__featured-work-column > a.homepage-intro__featured-tile`
ARTICLE · 6 MIN READ What do people die from in different countries? Hannah Ri… `section.homepage-intro > div.homepage-intro__featured-work > div.homepage-intro__featured-work-column > a.homepage-intro__featured-tile`
DATA UPDATE - YESTERDAY NVIDIA's data center & AI revenue has grown nearly 15-f… `div.homepage-intro__announcements > ul.homepage-intro__announcements-list > li.homepage-intro__announcement > a.homepage-intro__announcement-link`
DATA UPDATE - THIS WEEK Billions of people depend on synthetic fertilizers. Tra… `div.homepage-intro__announcements > ul.homepage-intro__announcements-list > li.homepage-intro__announcement > a.homepage-intro__announcement-link`
DATA UPDATE - 6 DAYS AGO How much do governments spend, and what do they spend … `div.homepage-intro__announcements > ul.homepage-intro__announcements-list > li.homepage-intro__announcement > a.homepage-intro__announcement-link`
TODAY Indoor air pollution causes almost three million premature deaths every … `div.latest-data-insights__viewport > ul.latest-data-insights__card-container > li.latest-data-insights__card > a.latest-data-insights__card__data-insight`
APRIL 18 Death rates for cervical cancer in the United Kingdom have fallen by … `div.latest-data-insights__viewport > ul.latest-data-insights__card-container > li.latest-data-insights__card > a.latest-data-insights__card__data-insight`

○Interactive controls are keyboard focusable

○Interactive elements indicate their purpose and state

○The page has a logical tab order

○Visual order on the page follows DOM order

○User focus is not accidentally trapped in a region

○The user's focus is directed to new content added to the page

○HTML5 landmark elements are used to improve navigation

○Offscreen content is hidden from assistive technology

○Custom controls have associated labels

○Custom controls have ARIA roles

●`[aria-*]` attributes match their roles

●`[aria-hidden="true"]` is not present on the document `<body>`

●`[role]`s have all required `[aria-*]` attributes

●`[role]` values are valid

●`[aria-*]` attributes have valid values

●`[aria-*]` attributes are valid and not misspelled

●Buttons have an accessible name

●Form elements have associated labels

●`[user-scalable="no"]` is not used in the `<meta name="viewport">` element and the `[maximum-scale]` attribute is not less than 5.

●ARIA attributes are used as specified for the element's role

●`[aria-hidden="true"]` elements do not contain focusable descendents

●Elements use only permitted ARIA attributes

●Document has a `<title>` element

●`<html>` element has a `[lang]` attribute

●`<html>` element has a valid value for its `[lang]` attribute

●Lists contain only `<li>` elements and script supporting elements (`<script>` and `<template>`).

●List items (`<li>`) are contained within `<ul>`, `<ol>` or `<menu>` parent elements

●No element has a `[tabindex]` value greater than 0

●Touch targets have sufficient size and spacing.

●Deprecated ARIA roles were not used

●ARIA IDs are unique

○`[accesskey]` values are unique

○`button`, `link`, and `menuitem` elements have accessible names

○Elements with `role="dialog"` or `role="alertdialog"` have accessible names.

○ARIA input fields have accessible names

○ARIA `meter` elements have accessible names

○ARIA `progressbar` elements have accessible names

○Elements with an ARIA `[role]` that require children to contain a specific `[role]` have all required children.

○`[role]`s are contained by their required parent element

○Elements with the `role=text` attribute do not have focusable descendents.

○ARIA toggle fields have accessible names

○ARIA `tooltip` elements have accessible names

○ARIA `treeitem` elements have accessible names

○The page contains a heading, skip link, or landmark region

○`<dl>`'s contain only properly-ordered `<dt>` and `<dd>` groups, `<script>`, `<template>` or `<div>` elements.

○Definition list items are wrapped in `<dl>` elements

○No form fields have multiple labels

○`<frame>` or `<iframe>` elements have a title

○`<html>` element has an `[xml:lang]` attribute with the same base language as the `[lang]` attribute.

○Input buttons have discernible text.

○`<input type="image">` elements have `[alt]` text

○The document does not use `<meta http-equiv="refresh">`

○`<object>` elements have alternate text

○Select elements have associated label elements.

○Skip links are focusable.

○Cells in a `<table>` element that use the `[headers]` attribute refer to table cells within the same table.

○`<th>` elements and elements with `[role="columnheader"/"rowheader"]` have data cells they describe.

○`[lang]` attributes have a valid value

○`<video>` elements contain a `<track>` element with `[kind="captions"]`

○Tables have different content in the summary attribute and `<caption>`.

○All heading elements contain content.

○Uses ARIA roles only on compatible elements

○Image elements do not have `[alt]` attributes that are redundant text.

○Identical links have the same purpose.

○Tables use `<caption>` instead of cells with the `[colspan]` attribute to indicate a caption.

○`<td>` elements in a large `<table>` have one or more table headers.

Best Practices

User Experience

Image display dimensions should match natural aspect ratio. Learn more about image aspect ratio.

Why this matters

Performance issues directly impact user engagement and conversion rates.

	URL	Aspect Ratio (Displayed)	Aspect Ratio (Actual)
featured image `a.homepage-intro__featured-tile > div.image > picture > img`	/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/014e8530-1d...	2400 x 1260 (1.90)	350 x 183 (1.91)
Featured image `a.homepage-intro__featured-tile > div.image > picture > img`	/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/b18a3db6-93...	2400 x 1260 (1.90)	350 x 183 (1.91)
Featured image `a.homepage-intro__featured-tile > div.image > picture > img`	/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/e8c1792e-59...	1200 x 630 (1.90)	350 x 183 (1.91)

General

Source maps translate minified code to the original source code. This helps developers debug in production. In addition, Lighthouse is able to provide further insights. Consider deploying source maps to take advantage of these benefits. Learn more about source maps.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL	Map URL
ourworldindata.org/assets/owid.mjs	ourworldindata.org/assets/owid.mjs.map

●Uses HTTPS

●Avoids deprecated APIs

●Avoids third-party cookies

●Allows users to paste into input fields

●Avoids requesting the geolocation permission on page load

●Avoids requesting the notification permission on page load

●Serves images with appropriate resolution

●Page has the HTML doctype

●Properly defines charset

●No browser errors logged to the console

●No issues in the `Issues` panel in Chrome Devtools

●Ensure CSP is effective against XSS attacks

●Use a strong HSTS policy

●Ensure proper origin isolation with COOP

●Mitigate clickjacking with XFO or CSP

●Mitigate DOM-based XSS with Trusted Types

●Detected JavaScript libraries

○Redirects HTTP traffic to HTTPS

SEO

Content Best Practices

Informative elements should aim for short, descriptive alternate text. Decorative elements can be ignored with an empty alt attribute. Learn more about the `alt` attribute.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
a.homepage-intro__featured-tile > div.image > picture > img `a.homepage-intro__featured-tile > div.image > picture > img`
div.GrapherWithFallback > figure.grapherPreview > picture > img.GrapherImage `div.GrapherWithFallback > figure.grapherPreview > picture > img.GrapherImage`

Format your HTML in a way that enables crawlers to better understand your app’s content.

○Structured data is valid

●Page isn’t blocked from indexing

●Document has a `<title>` element

●Document has a meta description

●Page has successful HTTP status code

●Links have descriptive text

●Links are crawlable

●robots.txt is valid

●Document has a valid `hreflang`

●Document has a valid `rel=canonical`

Results for https://ourworldindata.org

Site Health

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Top Priorities (5)

Fix Priority Matrix

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What fixing these means

Conversion Barriers

Speed (1)

Trust (2)

Content (1)

Navigation (3)

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What Inaction Is Costing You

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