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Lighthouse Mobile

· 0 checks — Mobile Lighthouse audit -- Performance, Accessibility, Best Practices, and SEO category breakdown.
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Detailed Report

Audit breakdown by category with detailed findings.

75

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

Performance issues directly impact user engagement and conversion rates.

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.

RequestCache TTLTransfer Size
/grapher/share-of-population-in-extreme-poverty.png?imWid...3600.0 s144.4 KiB
ourworldindata.org/grapher/mobile-cellular-subscriptions-per-100-people.png3600.0 s132.4 KiB
ourworldindata.org/grapher/child-mortality.png?time=earliest..latest&imWidth=8503600.0 s83.9 KiB
ourworldindata.org/explorers/climate-change.png0.0 ms62.3 KiB
ourworldindata.org/grapher/life-expectancy.png?imWidth=8503600.0 s73.8 KiB
/grapher/co-emissions-per-capita.png?tab=chart&country=US...3600.0 s71.8 KiB
/explorers/co2.png?facet=none&country=CHN~USA~IND~FRA&Gas...0.0 ms55.7 KiB
/grapher/technology-adoption-by-households-in-the-united-...3600.0 s63.2 KiB
/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/817073af-ee...172800.0 s90.3 KiB
/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/8a2c84fa-1d...172800.0 s80.1 KiB
/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/92713fbe-c3...172800.0 s76.2 KiB
/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/2b579c45-b1...172800.0 s67.6 KiB
/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/23d16973-25...172800.0 s66.1 KiB
/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/e3b40748-b3...172800.0 s56.3 KiB
/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/014e8530-1d...172800.0 s35.8 KiB
static.cloudflareinsights.com/beacon.min.js86400.0 s10.7 KiB
/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/e8c1792e-59...172800.0 s3.8 KiB
/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/b18a3db6-93...172800.0 s3.5 KiB
/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/c0176bc5-b9...172800.0 s1.7 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.

URLResource SizeEst 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 KiB56.1 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 KiB49.7 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 KiB47.3 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 KiB41.9 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 KiB41.0 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 KiB34.9 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=85083.4 KiB28.8 KiB
featured image a.homepage-intro__featured-tile > div.image > picture > img
/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/014e8530-1d...35.4 KiB24.6 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.

URLTotal CPU TimeScript EvaluationScript Parse
Unattributable1.5 s576 ms0.0 ms
ourworldindata.org/assets/owid.mjs932 ms708 ms12 ms
ourworldindata.org/687 ms15 ms19 ms
www.googletagmanager.com/gtm.js?id=GTM-N2D4V8S215 ms174 ms39 ms
www.googletagmanager.com/gtag/js?id=G-RSY8NMC3MT&cx=c&gtm=4e64h1175 ms143 ms31 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.

CategoryTime Spent
Script Evaluation1.6 s
Other1.0 s
Style & Layout517 ms
Rendering125 ms
Script Parsing & Compilation104 ms
Garbage Collection102 ms
Parse HTML & CSS57 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

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 0.0 ms 709.3 KiB
URLTransfer SizeEst Savings
ourworldindata.org/assets/owid.mjs986.6 KiB585.0 KiB
www.googletagmanager.com/gtag/js?id=G-RSY8NMC3MT&cx=c&gtm=4e64h1152.1 KiB64.1 KiB
www.googletagmanager.com/gtm.js?id=GTM-N2D4V8S130.1 KiB60.2 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.

URLTransfer Size
ourworldindata.org/assets/owid.mjs988.0 KiB
www.googletagmanager.com/gtag/js?id=G-RSY8NMC3MT&cx=c&gtm=4e64h1152.2 KiB
/grapher/share-of-population-in-extreme-poverty.png?imWid...144.4 KiB
ourworldindata.org/grapher/mobile-cellular-subscriptions-per-100-people.png132.4 KiB
www.googletagmanager.com/gtm.js?id=GTM-N2D4V8S130.5 KiB
ourworldindata.org/dods.json95.7 KiB
/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/817073af-ee...90.3 KiB
ourworldindata.org/grapher/child-mortality.png?time=earliest..latest&imWidth=85083.9 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
81

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.
96

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.

SourceDescription
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
92

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`

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