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

Audit breakdown by category with detailed findings.

61

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 s804.8 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s778.4 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 s757.5 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 s664.4 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 s436.2 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 s419.1 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 s280.9 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 s234.5 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 s203.1 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s196.0 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s192.8 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 s20.8 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s150.1 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 s133.6 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s124.3 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 s117.1 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 s111.5 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s109.0 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s106.4 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 s101.9 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s101.6 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 s85.6 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 s11.9 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 s75.5 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s69.4 KiB
/content/sites/www.columbia.edu.content/files/css/css_hkE...1209600.0 s66.8 KiB
use.typekit.net/rke7urc.js600.0 s7.1 KiB
/content/sites/www.columbia.edu.content/files/js/js_iBsAv...1209600.0 s64.0 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/styles/cu_c...1209600.0 s28.5 KiB
/content/sites/www.columbia.edu.content/files/js/js_I-A3z...1209600.0 s28.1 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s27.0 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s24.6 KiB
/content/sites/www.columbia.edu.content/files/css/css_nl2...1209600.0 s23.5 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s23.2 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s22.1 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...1209600.0 s19.8 KiB
/content/libraries/custom/ss-social-regular/webfonts/ss-s...1209600.0 s19.6 KiB
/content/themes/custom/columbia/assets/fonts/glyphicons-h...1209600.0 s18.0 KiB
/content/sites/www.columbia.edu.content/files/css/css_OSU...1209600.0 s17.3 KiB
www.columbia.edu/content/themes/custom/columbia/assets/img/cu-header.svg1209600.0 s14.2 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.js2869.0 s790 B
static.doubleclick.net/instream/ad_status.js900.0 s495 B
/content/sites/www.columbia.edu.content/files/js/js_JaDC_...1209600.0 s4.3 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
/content/sites/www.columbia.edu.content/files/css/css_trG...1209600.0 s1.5 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_EGo...1209600.0 s1.0 KiB
/content/sites/www.columbia.edu.content/files/css/css_7-s...1209600.0 s723 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-...125 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
/content/themes/custom/columbia/assets/fonts/glyphicons-h...35 ms
/af/efe4a5/00000000000000007735e609/30/l?primer=fff1a9895...30 ms
/af/1be3c2/00000000000000007735e606/30/l?primer=fff1a9895...30 ms
/af/78aca8/00000000000000007735e60d/30/l?primer=fff1a9895...25 ms
/af/23e139/00000000000000007735e605/30/l?primer=fff1a9895...20 ms
/af/2555e1/00000000000000007735e603/30/l?primer=fff1a9895...20 ms
/af/3322cc/00000000000000007735e616/30/l?primer=fff1a9895...20 ms
/af/6799c3/000000000000000000012e92/27/l?primer=7fa3915bd...15 ms
fonts.gstatic.com/s/roboto/v48/KFO7CnqEu92Fr1ME7kSn66aGLdTylUAMa3yUBHMdazQ.woff215 ms
/af/154cda/00000000000000007735e601/30/l?primer=fff1a9895...15 ms
/af/2011b6/00000000000000003b9b00c1/27/l?primer=7fa3915bd...10 ms
/af/5cace6/00000000000000003b9b00c2/27/l?primer=7fa3915bd...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:30.488 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:4.517 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:11.358 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:17.786 source:map[type:text value:[unattributed]]] map[reflowTime:0.302 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:28.634 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:0.518 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:0.381 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:0.382 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:0.573 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
GENERAL STUDIES Columbia General Studies to Partner on Mayor's Scholarship Prog… div.flickity-slider > div.highlights-cell > a.cell-item > div.cell-inner
/content/sites/www.columbia.edu.content/files/styles/cu_c...1.1 MiB1.0 MiB
Columbia Close-Up span > div.field > div.image-wrapper > img.img-responsive
/content/sites/www.columbia.edu.content/files/styles/cu_c...803.4 KiB791.5 KiB
LAW Columbia Law School Launches the Center for Law and the Economy, Led by Pro… div.flickity-slider > div.highlights-cell > a.cell-item > div.cell-inner
/content/sites/www.columbia.edu.content/files/styles/cu_c...756.2 KiB674.9 KiB
EVENT RECAP A Conversation on Middleware and User Control div.flickity-slider > div.highlights-cell > a.cell-item > div.cell-inner
/content/sites/www.columbia.edu.content/files/styles/cu_c...625.6 KiB544.3 KiB
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
signs of spring span > div.field > div.image-wrapper > img.img-responsive
/content/sites/www.columbia.edu.content/files/styles/cu_c...418.0 KiB406.2 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
CAMPUS & COMMUNITY Columbia Housing Upgrades Nine Residence Hall Fitness Centers div.flickity-slider > div.highlights-cell > a.cell-item > div.cell-inner
/content/sites/www.columbia.edu.content/files/styles/cu_c...669.1 KiB219.1 KiB
columbia ice hockey club span > div.field > div.image-wrapper > img.img-responsive
/content/sites/www.columbia.edu.content/files/styles/cu_c...202.5 KiB190.6 KiB
PHOTO OF THE WEEK Class Is in Session (Outdoors!) div.flickity-slider > div.highlights-cell > a.cell-item > div.cell-inner
/content/sites/www.columbia.edu.content/files/styles/cu_c...268.3 KiB187.0 KiB
JOURNALISM Professor Nina Alvarez’s Film 'Almost American' Re-Released div.flickity-slider > div.highlights-cell > a.cell-item > div.cell-inner
/content/sites/www.columbia.edu.content/files/styles/cu_c...418.6 KiB183.8 KiB
GRADUATION 2026 15 Great Places to Take Graduation Photos on Columbia's Campuse… div.flickity-slider > div.highlights-cell > a.cell-item > div.cell-inner
/content/sites/www.columbia.edu.content/files/styles/cu_c...263.4 KiB182.0 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 KiB145.2 KiB
NEIGHBORS At ‘Weather or Not 2.0,’ Local Youth and Women in STEM Take Center St… div.flickity-slider > div.highlights-cell > a.cell-item > div.cell-inner
/content/sites/www.columbia.edu.content/files/styles/cu_c...192.2 KiB131.1 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 KiB119.6 KiB
Butler Library span > div.field > div.image-wrapper > img.img-responsive
/content/sites/www.columbia.edu.content/files/styles/cu_c...111.1 KiB107.1 KiB
Kitty Henderson span > div.field > div.image-wrapper > img.img-responsive
/content/sites/www.columbia.edu.content/files/styles/cu_c...105.8 KiB101.9 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 KiB97.7 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 KiB97.2 KiB
GRADUATION 2026 Volunteer at Commencement, Get a Floating Day Off div.flickity-slider > div.highlights-cell > a.cell-item > div.cell-inner
/content/sites/www.columbia.edu.content/files/styles/cu_c...140.6 KiB95.8 KiB
COLUMBIA MAGAZINE Jennifer Crewe Retires from Columbia University Press div.flickity-slider > div.highlights-cell > a.cell-item > div.cell-inner
/content/sites/www.columbia.edu.content/files/styles/cu_c...184.5 KiB90.4 KiB
GRADUATION 2026 Meet the Sustainability Director Who Volunteers to Drive Columb… div.flickity-slider > div.highlights-cell > a.cell-item > div.cell-inner
/content/sites/www.columbia.edu.content/files/styles/cu_c...164.2 KiB82.8 KiB
OFF THE SHELF How Do You See What Cannot Be Seen? “Seeing becomes less about c… div.flickity-slider > div.highlights-cell > a.cell-item > div.cell-inner
/content/sites/www.columbia.edu.content/files/styles/cu_c...149.4 KiB68.1 KiB
AWARDS AND MILESTONES Three Columbians Named AAAS Fellows div.flickity-slider > div.highlights-cell > a.cell-item > div.cell-inner
/content/sites/www.columbia.edu.content/files/styles/cu_c...149.3 KiB67.9 KiB
COLUMBIA MAGAZINE The New Red Scare div.flickity-slider > div.highlights-cell > a.cell-item > div.cell-inner
/content/sites/www.columbia.edu.content/files/styles/cu_c...164.0 KiB66.1 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
Commencement throwing caps in the air span > div.field > div.image-wrapper > img.img-responsive
/content/sites/www.columbia.edu.content/files/styles/cu_c...28.0 KiB25.6 KiB
COLUMBIA MAGAZINE The Alarming Consequences of Legal Sports Gambling div.flickity-slider > div.highlights-cell > a.cell-item > div.cell-inner
/content/sites/www.columbia.edu.content/files/styles/cu_c...140.5 KiB24.3 KiB
scholars lion with the magnolias in the background span > div.field > div.image-wrapper > img.img-responsive
/content/sites/www.columbia.edu.content/files/styles/cu_c...26.5 KiB24.1 KiB
students sitting in front of low library on the steps span > div.field > div.image-wrapper > img.img-responsive
/content/sites/www.columbia.edu.content/files/styles/cu_c...24.1 KiB21.7 KiB
Three students walk across the brooklyn bridge span > div.field > div.image-wrapper > img.img-responsive
/content/sites/www.columbia.edu.content/files/styles/cu_c...22.8 KiB20.5 KiB
COLUMBIA ENGINEERING How Electric Cars Could Help Tropical Cities Run on Solar div.flickity-slider > div.highlights-cell > a.cell-item > div.cell-inner
/content/sites/www.columbia.edu.content/files/styles/cu_c...100.7 KiB19.3 KiB
The Thinker near magnolias trees span > div.field > div.image-wrapper > img.img-responsive
/content/sites/www.columbia.edu.content/files/styles/cu_c...21.5 KiB19.2 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
Columbias staffers at a dining event span > div.field > div.image-wrapper > img.img-responsive
/content/sites/www.columbia.edu.content/files/styles/cu_c...19.4 KiB17.0 KiB

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-6-DIV
nodeLabel: A photo of a forest
path: 1,HTML,1,BODY,1,DIV,2,DIV,5,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...133.6 KiB121 ms
code.jquery.com/ui/1.12.1/jquery-ui.min.js66.3 KiB203 ms
/ajax/libs/moment-timezone/0.5.43/moment-timezone-with-da...26.2 KiB337 ms
/content/sites/www.columbia.edu.content/files/js/js_I-A3z...28.1 KiB81 ms
/content/sites/www.columbia.edu.content/files/js/js_QB5Aa...3.9 KiB
/content/sites/www.columbia.edu.content/files/js/js_-VfW5...31.8 KiB121 ms
/content/sites/www.columbia.edu.content/files/css/css_hkE...66.8 KiB242 ms
use.typekit.net/rke7urc.js7.1 KiB209 ms
/content/sites/www.columbia.edu.content/files/css/css_OSU...17.3 KiB
cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.21/lodash.min.js23.2 KiB289 ms
/content/sites/www.columbia.edu.content/files/css/css_nl2...23.5 KiB
/content/sites/www.columbia.edu.content/files/css/css_EGo...1.0 KiB
/content/sites/www.columbia.edu.content/files/css/css_hp7...2.3 KiB
code.jquery.com/ui/1.12.1/themes/base/jquery-ui.css8.4 KiB204 ms

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

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: 448 ms
URLTime Spent
columbia.edu/217 ms
www.columbia.edu/231 ms
www.columbia.edu/0.0 ms

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.

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: 80 ms 97.1 KiB
URLTransfer SizeEst Savings
/content/sites/www.columbia.edu.content/files/css/css_hkE...66.4 KiB59.7 KiB
/content/sites/www.columbia.edu.content/files/css/css_nl2...23.0 KiB21.1 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: 160 ms 297.3 KiB
URLTransfer SizeEst Savings
/content/sites/www.columbia.edu.content/files/js/js_NDpNd...133.2 KiB72.9 KiB
www.googletagmanager.com/gtag/js?id=G-09H1KYXPLX&cx=c&gtm=4e64k0h2157.7 KiB63.3 KiB
www.googletagmanager.com/gtag/js?id=UA-18290390-1115.5 KiB63.1 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 KiB38.8 KiB

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...804.8 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...778.4 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...764.9 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...757.5 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...670.4 KiB
/content/sites/www.columbia.edu.content/files/styles/cu_c...664.4 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

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

●Layout shift culprits
●Optimize DOM size
●LCP breakdown
●Modern HTTP
●Optimize viewport for mobile
●Minify CSS
●User Timing marks and measures 5 user timings
●JavaScript execution time 0.8 s
●Minimizes main-thread work 1.7 s
●Avoid long main-thread tasks 4 long tasks found
●Image elements have explicit `width` and `height`
●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
●Initial server response time was short Root document took 30 ms
●Avoid large layout shifts 1 layout shift found
○INP breakdown
○Avoid non-composited animations
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
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.
●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
○`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 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.
54

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 ()

Issues logged to the `Issues` panel in Chrome Devtools indicate unresolved problems. They can come from network request failures, insufficient security controls, and other browser concerns. Open up the Issues panel in Chrome DevTools for more details on each issue.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Issue type
Content security policy
●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
●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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