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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.

31

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 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
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s1.1 MiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s778.3 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s764.9 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s757.7 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s670.4 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s664.6 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s626.9 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s528.7 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s521.9 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s436.3 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s419.6 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s398.9 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s324.2 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s300.2 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s281.1 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s279.3 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s269.2 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s264.2 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s234.4 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s219.1 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s209.2 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s195.9 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s192.9 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s185.2 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s176.7 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s164.9 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s164.7 KiB
www.google-analytics.com/analytics.js7200.0 s20.9 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s150.2 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s150.0 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s149.9 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s141.4 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s141.2 KiB
/content/sites/www.columbia.edu.content/files/js/js_NDpNd...1209600.0 s133.8 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s124.2 KiB
i.ytimg.com/vi_webp/6gjLTck1gLY/sddefault.webp7200.0 s15.9 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s117.3 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s116.6 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s111.7 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s108.9 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s106.5 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s102.3 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s101.8 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s101.8 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s101.4 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s99.6 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s92.6 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s85.7 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s85.1 KiB
/cdn-cgi/challenge-platform/h/b/scripts/jsd/0b8fb825cb67/...14400.0 s12.0 KiB
player.vimeo.com/api/player.js1800.0 s8.9 KiB
/content/libraries/custom/font-awesome/fonts/fontawesome-...1209600.0 s76.0 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s75.7 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s69.3 KiB
/content/sites/www.columbia.edu.content/files/css/css_hkE...1209600.0 s66.9 KiB
use.typekit.net/rke7urc.js600.0 s7.1 KiB
/content/sites/www.columbia.edu.content/files/js/js_iBsAv...1209600.0 s64.2 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s49.8 KiB
/content/sites/www.columbia.edu.content/files/js/js_-VfW5...1209600.0 s31.8 KiB
/content/sites/www.columbia.edu.content/files/js/js_I-A3z...1209600.0 s28.3 KiB
/content/sites/www.columbia.edu.content/files/css/css_nl2...1209600.0 s23.6 KiB
www.columbia.edu/content/themes/custom/columbia/assets/img/left_gray_out.png1209600.0 s21.6 KiB
www.columbia.edu/content/themes/custom/columbia/assets/img/right_gray_out.png1209600.0 s21.5 KiB
/content/libraries/custom/ss-social-regular/webfonts/ss-s...1209600.0 s19.6 KiB
/content/sites/www.columbia.edu.content/files/css/css_OSU...1209600.0 s17.2 KiB
www.columbia.edu/content/themes/custom/columbia/assets/img/cu-header.svg1209600.0 s14.3 KiB
www.columbia.edu/content/themes/custom/columbia/assets/img/cu-blue-logo.svg1209600.0 s14.1 KiB
www.columbia.edu/cdn-cgi/scripts/5c5dd728/cloudflare-static/email-decode.min.js2868.0 s786 B
static.doubleclick.net/instream/ad_status.js900.0 s495 B
/content/sites/www.columbia.edu.content/files/js/js_JaDC_...1209600.0 s4.4 KiB
/content/sites/www.columbia.edu.content/files/js/js_QB5Aa...1209600.0 s3.9 KiB
/content/sites/www.columbia.edu.content/files/css/css_hp7...1209600.0 s2.3 KiB
www.columbia.edu/content/themes/custom/columbia/assets/fonts/x-com.ttf1209600.0 s1.4 KiB
/content/sites/www.columbia.edu.content/files/css/css_trG...1209600.0 s1.4 KiB
/content/sites/www.columbia.edu.content/files/css/css_EGo...1209600.0 s1.0 KiB
/content/sites/www.columbia.edu.content/files/css/css_7-s...1209600.0 s924 B
/p.gif?s=1&k=rke7urc&ht=tk&h=www.columbia.edu&f=139.171.1...604800.0 s205 B
i.ytimg.com/vi_webp/6gjLTck1gLY/sddefault.webp7200.0 s0 B
static.doubleclick.net/instream/ad_status.js900.0 s0 B

Your first network request is the most important. Reduce its latency by avoiding redirects, ensuring a fast server response, and enabling text compression.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Consider setting font-display to swap or optional to ensure text is consistently visible. swap can be further optimized to mitigate layout shifts with font metric overrides.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URLEst Savings
/content/libraries/custom/font-awesome/fonts/fontawesome-...85 ms
/content/libraries/custom/ss-social-regular/webfonts/ss-s...85 ms
www.columbia.edu/content/themes/custom/columbia/assets/fonts/x-com.ttf85 ms
/af/2555e1/00000000000000007735e603/30/l?primer=fff1a9895...35 ms
/af/23e139/00000000000000007735e605/30/l?primer=fff1a9895...25 ms
/af/1be3c2/00000000000000007735e606/30/l?primer=fff1a9895...25 ms
/af/5cace6/00000000000000003b9b00c2/27/l?primer=7fa3915bd...20 ms
/af/2011b6/00000000000000003b9b00c1/27/l?primer=7fa3915bd...20 ms
/af/efe4a5/00000000000000007735e609/30/l?primer=fff1a9895...15 ms
/af/6799c3/000000000000000000012e92/27/l?primer=7fa3915bd...15 ms
/af/78aca8/00000000000000007735e60d/30/l?primer=fff1a9895...15 ms
/af/3322cc/00000000000000007735e616/30/l?primer=fff1a9895...15 ms
fonts.gstatic.com/s/roboto/v48/KFO7CnqEu92Fr1ME7kSn66aGLdTylUAMa3yUBHMdazQ.woff210 ms
/af/154cda/00000000000000007735e601/30/l?primer=fff1a9895...5.0 ms

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:Top function call valueType:source-location] map[granularity:1 key:reflowTime label:Total reflow time valueType:ms]]
items: [map[reflowTime:30.749 source:map[column:27323 line:3 type:source-location url:https://www.columbia.edu/content/sites/www.columbia.edu.content/files/js/js_-VfW5OTnd-614WcPt0EhMj80XeH_mO_fMqAs2ygFCfE.js?qs=9a87463107391083ae41a44cdd03a374 urlProvider:network]]]
headings: [map[key:source label:Source valueType:source-location] map[granularity:1 key:reflowTime label:Total reflow time valueType:ms]]
items: [map[reflowTime:19.098 source:map[column:7662 line:9 type:source-location url:https://www.columbia.edu/content/sites/www.columbia.edu.content/files/js/js_iBsAvH-N2woJFVjmYPshSnQtRNgBdHjpEEZSo-7-tf4.js?qs=aca78062e4b4e688f8c9675aa5f2f24b urlProvider:network]] map[reflowTime:65.735 source:map[column:7687 line:9 type:source-location url:https://www.columbia.edu/content/sites/www.columbia.edu.content/files/js/js_iBsAvH-N2woJFVjmYPshSnQtRNgBdHjpEEZSo-7-tf4.js?qs=aca78062e4b4e688f8c9675aa5f2f24b urlProvider:network]] map[reflowTime:34.544 source:map[type:text value:[unattributed]]] map[reflowTime:5.762 source:map[column:113 line:1 type:source-location url:https://www.columbia.edu/content/sites/www.columbia.edu.content/files/js/js_iBsAvH-N2woJFVjmYPshSnQtRNgBdHjpEEZSo-7-tf4.js?qs=aca78062e4b4e688f8c9675aa5f2f24b urlProvider:network]] map[reflowTime:6.804 source:map[column:500 line:11 type:source-location url:https://www.columbia.edu/content/sites/www.columbia.edu.content/files/js/js_NDpNdspfAthpa2cWemm86171HkiPGGIngLjnzYTxBmw.js?qs=168d8d191de5b5bf20f9320b672d955e urlProvider:network]] map[reflowTime:22.096 source:map[column:49615 line:2 type:source-location url:https://www.columbia.edu/content/sites/www.columbia.edu.content/files/js/js_-VfW5OTnd-614WcPt0EhMj80XeH_mO_fMqAs2ygFCfE.js?qs=9a87463107391083ae41a44cdd03a374 urlProvider:network]] map[reflowTime:0.534 source:map[column:50335 line:2 type:source-location url:https://www.columbia.edu/content/sites/www.columbia.edu.content/files/js/js_-VfW5OTnd-614WcPt0EhMj80XeH_mO_fMqAs2ygFCfE.js?qs=9a87463107391083ae41a44cdd03a374 urlProvider:network]] map[reflowTime:0.374 source:map[column:50393 line:2 type:source-location url:https://www.columbia.edu/content/sites/www.columbia.edu.content/files/js/js_-VfW5OTnd-614WcPt0EhMj80XeH_mO_fMqAs2ygFCfE.js?qs=9a87463107391083ae41a44cdd03a374 urlProvider:network]] map[reflowTime:0.374 source:map[column:50457 line:2 type:source-location url:https://www.columbia.edu/content/sites/www.columbia.edu.content/files/js/js_-VfW5OTnd-614WcPt0EhMj80XeH_mO_fMqAs2ygFCfE.js?qs=9a87463107391083ae41a44cdd03a374 urlProvider:network]] map[reflowTime:0.567 source:map[column:51395 line:2 type:source-location url:https://www.columbia.edu/content/sites/www.columbia.edu.content/files/js/js_-VfW5OTnd-614WcPt0EhMj80XeH_mO_fMqAs2ygFCfE.js?qs=9a87463107391083ae41a44cdd03a374 urlProvider:network]]]

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
Children throw bags at corn hole target at Manhattanville Community Day div.field--item > div#cu_www_hero_image-6597 > div.image-slide-inner > div#hero-image-bg-6597
/content/sites/www.columbia.edu.content/files/styles/cu_c...527.5 KiB485.0 KiB
A photo of a forest div.carousel-inner > div#cu_www_hero_image-20724 > div.image-slide-inner > div#hero-image-bg-20724
/content/sites/www.columbia.edu.content/files/styles/cu_c...435.1 KiB252.8 KiB
A laptop with Columbia News on it div.field--item > div#cu_www_hero_image-6601 > div.image-slide-inner > div#hero-image-bg-6601
/content/sites/www.columbia.edu.content/files/styles/cu_c...323.3 KiB148.7 KiB
CUIMC MEdical center span > div.field > div.image-wrapper > img.img-responsive
/content/sites/www.columbia.edu.content/files/styles/cu_c...149.2 KiB135.4 KiB
Low Library on a sunny day span > div.field > div.image-wrapper > img.img-responsive
/content/sites/www.columbia.edu.content/files/styles/cu_c...123.6 KiB109.8 KiB
Butler Library span > div.field > div.image-wrapper > img.img-responsive
/content/sites/www.columbia.edu.content/files/styles/cu_c...111.1 KiB97.3 KiB
Kitty Henderson span > div.field > div.image-wrapper > img.img-responsive
/content/sites/www.columbia.edu.content/files/styles/cu_c...105.8 KiB92.1 KiB
Morningside Lights lanterns span > div.field > div.image-wrapper > img.img-responsive
/content/sites/www.columbia.edu.content/files/styles/cu_c...101.7 KiB87.9 KiB
Students with inflatable globes span > div.field > div.image-wrapper > img.img-responsive
/content/sites/www.columbia.edu.content/files/styles/cu_c...101.2 KiB87.4 KiB
NURSING What New Columbia Nursing Studies Reveal About AI and Digital Health in… div.flickity-slider > div.highlights-cell > a.cell-item > div.cell-inner
/content/sites/www.columbia.edu.content/files/styles/cu_c...208.4 KiB29.7 KiB
AWARDS AND MILESTONES Professor J. Colin Hill Awarded Breakthrough New Horizons… div.flickity-slider > div.highlights-cell > a.cell-item > div.cell-inner
/content/sites/www.columbia.edu.content/files/styles/cu_c...108.3 KiB26.9 KiB
section#cu_tabbed_content-15469 > div.tab-group > div.tab-wrapper > ::after section#cu_tabbed_content-15469 > div.tab-group > div.tab-wrapper > ::after
www.columbia.edu/content/themes/custom/columbia/assets/img/right_gray_out.png21.0 KiB20.7 KiB
section#cu_tabbed_content-15469 > div.tab-group > div.tab-wrapper > ::before section#cu_tabbed_content-15469 > div.tab-group > div.tab-wrapper > ::before
www.columbia.edu/content/themes/custom/columbia/assets/img/left_gray_out.png21.0 KiB20.7 KiB
COLUMBIA COLLEGE TODAY Ellen Lansing (CC’26) Has a Passion for Climate Action div.flickity-slider > div.highlights-cell > a.cell-item > div.cell-inner
/content/sites/www.columbia.edu.content/files/styles/cu_c...99.0 KiB17.6 KiB

Each subpart has specific improvement strategies. Ideally, most of the LCP time should be spent on loading the resources, not within delays.

Why this matters

Performance issues directly impact user engagement and conversion rates.

headings: [map[key:label label:Subpart valueType:text] map[key:duration label:Duration valueType:ms]]
items: [map[duration:69.792 label:Time to first byte subpart:timeToFirstByte] map[duration:1119.523 label:Resource load delay subpart:resourceLoadDelay] map[duration:51.159 label:Resource load duration subpart:resourceLoadDuration] map[duration:1745.791 label:Element render delay subpart:elementRenderDelay]]
lhId: page-1-DIV
nodeLabel: A photo of a forest
path: 1,HTML,1,BODY,1,DIV,2,DIV,3,MAIN,1,DIV,0,SECTION,0,DIV,1,DIV,0,ARTICLE,0,DIV,0,DIV,0,ARTICLE,0,DIV,0,DIV,1,DIV,0,DIV,1,DIV,0,DIV
selector: div.carousel-inner > div#cu_www_hero_image-20724 > div.image-slide-inner > div#hero-image-bg-20724
snippet: <div id="hero-image-bg-20724" class="field field--name-field-cu-image field--type-image field--label-hidden ima…" data-image="https://www.columbia.edu/content/sites/www.columbia.edu.content/files/styl…" style="background-image: url(&quot;https://www.columbia.edu/content/sites/www.columbia…&quot;);" role="img" aria-label="A photo of a forest">

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-1-DIV
nodeLabel: A photo of a forest
path: 1,HTML,1,BODY,1,DIV,2,DIV,3,MAIN,1,DIV,0,SECTION,0,DIV,1,DIV,0,ARTICLE,0,DIV,0,DIV,0,ARTICLE,0,DIV,0,DIV,1,DIV,0,DIV,1,DIV,0,DIV
selector: div.carousel-inner > div#cu_www_hero_image-20724 > div.image-slide-inner > div#hero-image-bg-20724
snippet: <div id="hero-image-bg-20724" class="field field--name-field-cu-image field--type-image field--label-hidden ima…" data-image="https://www.columbia.edu/content/sites/www.columbia.edu.content/files/styl…" style="background-image: url(&quot;https://www.columbia.edu/content/sites/www.columbia…&quot;);" role="img" aria-label="A photo of a forest">

Avoid chaining critical requests by reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources to improve page load.

Why this matters

Performance issues directly impact user engagement and conversion rates.

description: [preconnect](https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/) hints help the browser establish a connection earlier in the page load, saving time when the first request for that origin is made. The following are the origins that the page preconnected to.
title: Preconnected origins
description: Add [preconnect](https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/) hints to your most important origins, but try to use no more than 4.
title: Preconnect candidates

Requests are blocking the page's initial render, which may delay LCP. Deferring or inlining can move these network requests out of the critical path.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URLTransfer SizeDuration
/content/sites/www.columbia.edu.content/files/js/js_NDpNd...133.8 KiB2.1 s
/ajax/libs/moment-timezone/0.5.43/moment-timezone-with-da...26.2 KiB1.8 s
/content/sites/www.columbia.edu.content/files/js/js_I-A3z...28.3 KiB451 ms
/content/sites/www.columbia.edu.content/files/js/js_QB5Aa...3.9 KiB
code.jquery.com/ui/1.12.1/jquery-ui.min.js66.5 KiB1.8 s
/content/sites/www.columbia.edu.content/files/js/js_-VfW5...31.8 KiB602 ms
/content/sites/www.columbia.edu.content/files/css/css_hkE...66.9 KiB1.5 s
/content/sites/www.columbia.edu.content/files/css/css_nl2...23.6 KiB903 ms
cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.21/lodash.min.js23.2 KiB1.6 s
use.typekit.net/rke7urc.js7.1 KiB152 ms
/content/sites/www.columbia.edu.content/files/css/css_EGo...1.0 KiB
/content/sites/www.columbia.edu.content/files/css/css_OSU...17.2 KiB752 ms
/content/sites/www.columbia.edu.content/files/css/css_hp7...2.3 KiB
code.jquery.com/ui/1.12.1/themes/base/jquery-ui.css8.2 KiB907 ms

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

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

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.

Redirects introduce additional delays before the page can be loaded. Learn how to avoid page redirects.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 1.5 s
URLTime Spent
columbia.edu/766 ms
www.columbia.edu/781 ms
www.columbia.edu/0.0 ms

Diagnostics

Reduce unused rules from stylesheets and defer CSS not used for above-the-fold content to decrease bytes consumed by network activity. Learn how to reduce unused CSS.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 600 ms 98.5 KiB
URLTransfer SizeEst Savings
/content/sites/www.columbia.edu.content/files/css/css_hkE...66.4 KiB60.5 KiB
/content/sites/www.columbia.edu.content/files/css/css_nl2...23.0 KiB21.6 KiB
/content/sites/www.columbia.edu.content/files/css/css_OSU...16.7 KiB16.4 KiB

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: 1.7 s 296.9 KiB
URLTransfer SizeEst Savings
/content/sites/www.columbia.edu.content/files/js/js_NDpNd...133.2 KiB72.5 KiB
www.googletagmanager.com/gtag/js?id=G-09H1KYXPLX&cx=c&gtm=4e64k0h2157.7 KiB63.7 KiB
www.googletagmanager.com/gtag/js?id=UA-18290390-1115.5 KiB63.0 KiB
code.jquery.com/ui/1.12.1/jquery-ui.min.js66.2 KiB59.1 KiB
/content/sites/www.columbia.edu.content/files/js/js_iBsAv...63.6 KiB38.5 KiB

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
/content/sites/www.columbia.edu.content/files/js/js_-VfW5...2.6 s1.7 s12 ms
Unattributable1.1 s115 ms0.0 ms
www.columbia.edu/686 ms82 ms27 ms
/content/sites/www.columbia.edu.content/files/js/js_iBsAv...489 ms102 ms34 ms
www.columbia.edu/cdn-cgi/challenge-platform/scripts/jsd/main.js386 ms372 ms4.4 ms
www.googletagmanager.com/gtag/js?id=UA-18290390-1257 ms193 ms40 ms
www.googletagmanager.com/gtag/js?id=G-09H1KYXPLX&cx=c&gtm=4e64k0h2247 ms189 ms56 ms
/content/sites/www.columbia.edu.content/files/js/js_NDpNd...138 ms41 ms54 ms
/ajax/libs/moment-timezone/0.5.43/moment-timezone-with-da...129 ms40 ms88 ms
code.jquery.com/ui/1.12.1/jquery-ui.min.js67 ms38 ms28 ms
/content/sites/www.columbia.edu.content/files/css/css_hkE...64 ms0.0 ms0.0 ms
www.google-analytics.com/analytics.js64 ms56 ms6.9 ms
/content/sites/www.columbia.edu.content/files/js/js_I-A3z...55 ms45 ms10 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 Evaluation3.1 s
Other1.3 s
Style & Layout780 ms
Parse HTML & CSS469 ms
Script Parsing & Compilation389 ms
Garbage Collection242 ms
Rendering134 ms

Many navigations are performed by going back to a previous page, or forwards again. The back/forward cache (bfcache) can speed up these return navigations. Learn more about the bfcache

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failure reasonFailure type
Pages with cache-control:no-store header cannot enter back/forward cache.Actionable
Pages whose main resource has cache-control:no-store cannot enter back/forward cache.Not actionable
Back/forward cache is disabled because some JavaScript network request received resource with Cache-Control: no-store header.Not actionable

Minifying JavaScript files can reduce payload sizes and script parse time. Learn how to minify JavaScript.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 0.0 ms 6.8 KiB
URLTransfer SizeEst Savings
inline: if (typeof(events_data) == "undefined")…7.8 KiB3.4 KiB
inline: if (typeof(events_data) == "undefined")…7.6 KiB3.3 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.

URLTransfer Size
/content/sites/www.columbia.edu.content/files/styles/cu_c...1.1 MiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...778.3 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...764.9 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...757.7 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...670.4 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...664.6 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...626.9 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...528.7 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...521.9 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...436.3 KiB

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

●Layout shift culprits
●Optimize DOM size
●Modern HTTP
●Optimize viewport for mobile
●Minify CSS
●User Timing marks and measures 5 user timings
●Avoid long main-thread tasks 17 long tasks found
●Image elements have explicit `width` and `height`
●Network Requests
●Network Round Trip Times 10 ms
●Server Backend Latencies 30 ms
●Tasks
●Diagnostics
●Metrics
●Screenshot Thumbnails
●Final Screenshot
●Script Treemap Data
●Resources Summary
●Initial server response time was short Root document took 30 ms
○INP breakdown
○Avoid non-composited animations
○Avoid large layout shifts
100

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.

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
Athletics div.card-inner > div.field--item > div#cu_media_card-11624 > a.card-link
Arts div.card-inner > div.field--item > div#cu_media_card-11627 > a.card-link
Campus Access div.card-inner > div.field--item > div#cu_media_card-11633 > a.card-link
Giving div.card-inner > div.field--item > div#cu_media_card-11630 > a.card-link
Libraries div.card-inner > div.field--item > div#cu_media_card-11636 > a.card-link
Medical Center div.card-inner > div.field--item > div#cu_media_card-11639 > a.card-link
lightbulb icon Have an Idea About the Future of Research? div.field > div.field--item > div#cu_info_card-15424 > a.card-link
users icon Contact Our Elected Officials div.field > div.field--item > div#cu_info_card-15427 > a.card-link
building icon Connect With Policy and Advocacy Organizations div.field > div.field--item > div#cu_info_card-15430 > a.card-link
check-square icon Take Action for Columbia div.field > div.field--item > div#cu_info_card-15556 > a.card-link
WORLD LEADERS FORUM Can Europe Act? Power and Sovereignty in a Fragmenting Worl… div.flickity-viewport > div.flickity-slider > div.highlights-cell > a.cell-item
AWARDS AND MILESTONES Professor J. Colin Hill Awarded Breakthrough New Horizons… div.flickity-viewport > div.flickity-slider > div.highlights-cell > a.cell-item
Academic Calendar div.card-inner > div.field--item > div#cu_media_card-6533 > a.card-link
Summer Session div.card-inner > div.field--item > div#cu_media_card-6537 > a.card-link
Visiting Campus div.card-inner > div.field--item > div#cu_media_card-6541 > a.card-link
Commencement div.card-inner > div.field--item > div#cu_media_card-6545 > a.card-link
Careers div.card-inner > div.field--item > div#cu_media_card-6549 > a.card-link
Columbia Data div.card-inner > div.field--item > div#cu_media_card-6553 > a.card-link
Signs of Spring on Columbia’s Morningside Campus div.card-inner > div.field--item > div#cu_media_card-12798 > a.card-link
Can AI Make City Streets Safer? Columbia University Researchers Are Working on … div.card-inner > div.field--item > div#cu_media_card-6569 > a.card-link
It’s All About Team Spirit With the Columbia Ice Hockey Club div.card-inner > div.field--item > div#cu_media_card-6565 > a.card-link
Morningside Heights div.card-inner > div.field--item > div#cu_media_card-6609 > a.card-link
Irving Medical Center div.card-inner > div.field--item > div#cu_media_card-6613 > a.card-link
Manhattanville div.card-inner > div.field--item > div#cu_media_card-6617 > a.card-link
Lamont-Doherty Earth Observatory div.card-inner > div.field--item > div#cu_media_card-6621 > a.card-link
Baker Athletics Complex div.card-inner > div.field--item > div#cu_media_card-6625 > a.card-link
Columbia Global Centers div.card-inner > div.field--item > div#cu_media_card-6629 > a.card-link
○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
●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
●`[role]` values are valid
●`[aria-*]` attributes have valid values
●`[aria-*]` attributes are valid and not misspelled
●Buttons have an accessible name
●Image elements have `[alt]` attributes
●`[user-scalable="no"]` is not used in the `<meta name="viewport">` element and the `[maximum-scale]` attribute is not less than 5.
●`button`, `link`, and `menuitem` elements have accessible names
●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
●ARIA toggle fields have accessible names
●Background and foreground colors have a sufficient contrast ratio
●Document has a `<title>` element
●`<frame>` or `<iframe>` elements have a title
●`<html>` element has a `[lang]` attribute
●`<html>` element has a valid value for its `[lang]` attribute
●Links are distinguishable without relying on color.
●Links have a discernible name
●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.
●Heading elements appear in a sequentially-descending order
●Document has a main landmark.
●Deprecated ARIA roles were not used
○`[accesskey]` values are unique
○Elements with `role="dialog"` or `role="alertdialog"` have accessible names.
○ARIA `meter` elements have accessible names
○ARIA `progressbar` elements have accessible names
○Elements with the `role=text` attribute do not have focusable descendents.
○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
○ARIA IDs are unique
○No form fields have multiple labels
○`<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.
58

Best Practices

Trust and Safety

All sites should be protected with HTTPS, even ones that don't handle sensitive data. This includes avoiding mixed content, where some resources are loaded over HTTP despite the initial request being served over HTTPS. HTTPS prevents intruders from tampering with or passively listening in on the communications between your app and your users, and is a prerequisite for HTTP/2 and many new web platform APIs. Learn more about HTTPS.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Insecure URLRequest Resolution
www.columbia.edu/Allowed

General

Deprecated APIs will eventually be removed from the browser. Learn more about deprecated APIs.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Deprecation / WarningSource
SharedStorage
www.columbia.edu/cdn-cgi/challenge-platform/scripts/jsd/main.js
StorageType.persistent is deprecated. Please use standardized navigator.storage instead.
www.columbia.edu/cdn-cgi/challenge-platform/scripts/jsd/main.js
Fledge
www.columbia.edu/cdn-cgi/challenge-platform/scripts/jsd/main.js

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
www.columbia.edu/modules/custom/columbia/cu_utility_functions/www-keywords.php
Failed to load resource: the server responded with a status of 404 ()
●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 DOM-based XSS with Trusted Types
●Detected JavaScript libraries
●Page has valid source maps
○Redirects HTTP traffic to HTTPS
○Mitigate clickjacking with XFO or CSP
83

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

Meta descriptions may be included in search results to concisely summarize page content. Learn more about the meta description.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Descriptive link text helps search engines understand your content. Learn how to make links more accessible.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Link destinationLink Text
bit.ly/4txUPsaRead More
bit.ly/4sfO9hnRead More
/content/columbia-university-names-jennifer-mnookin-presi...Read More

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
●Page has successful HTTP status code
●Links are crawlable
●Image elements have `[alt]` attributes
●Document has a valid `hreflang`
●Document has a valid `rel=canonical`
○robots.txt is valid

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