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Lighthouse Desktop

· 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.

96

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:38.731 source:map[type:text value:[unattributed]]] map[reflowTime:0.708 source:map[column:9120 line:0 type:source-location url:https://www.nber.org/themes/custom/nber/assets/build/js/index-generated.js?tduart urlProvider:network]] map[reflowTime:0.294 source:map[column:849110 line:0 type:source-location url:https://www.nber.org/themes/custom/nber/assets/build/js/libraries-generated.js?tduart urlProvider:network]] map[reflowTime:0.155 source:map[column:849172 line:0 type:source-location url:https://www.nber.org/themes/custom/nber/assets/build/js/libraries-generated.js?tduart urlProvider:network]] map[reflowTime:0.127 source:map[column:849240 line:0 type:source-location url:https://www.nber.org/themes/custom/nber/assets/build/js/libraries-generated.js?tduart 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
(L to R) Marjorie B. McElroy, N. Gregory Mankiw, and Robert A. Margo div.promo-grid__multi-promo > div.home-left-rail__item > a.home-left-rail__item-promo-image-link > img.home-left-rail__item-promo-image
/sites/default/files/styles/homepage_feature_horizontal/p...65.1 KiB49.1 KiB
Program Report: Development Economics Figure 1 div.promo-grid__multi-promo > div.home-left-rail__item > a.home-left-rail__item-promo-image-link > img.home-left-rail__item-promo-image
/sites/default/files/styles/homepage_feature_horizontal/p...63.9 KiB47.9 KiB
w34317.jpg div.promo-grid__multi-promo > div.home-left-rail__item > a.home-left-rail__item-promo-image-link > img.home-left-rail__item-promo-image
/sites/default/files/styles/homepage_feature_horizontal/p...62.7 KiB47.0 KiB
Capital Gains Taxation and Startup Founders figure div.promo-grid__multi-promo > div.home-left-rail__item > a.home-left-rail__item-promo-image-link > img.home-left-rail__item-promo-image
/sites/default/files/styles/homepage_feature_horizontal/p...60.5 KiB45.4 KiB
The Impact of Expanding Paternity Leave Primary tabs div.promo-grid__multi-promo > div.home-left-rail__item > a.home-left-rail__item-promo-image-link > img.home-left-rail__item-promo-image
/sites/default/files/styles/homepage_feature_horizontal/p...59.3 KiB44.5 KiB

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
value: No additional origins are good candidates for preconnecting

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
www.google-analytics.com/analytics.js7200.0 s20.9 KiB

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
www.nber.org/themes/custom/nber/assets/fonts/TiemposHeadlineWeb-Semibold.woff215 ms
www.nber.org/themes/custom/nber/assets/fonts/TiemposHeadlineWeb-Regular.woff5.0 ms

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 Size
www.nber.org/themes/custom/nber/assets/build/css/nber-generated.css?tduart46.0 KiB
/core/modules/system/css/components/position-container.mo...401 B
www.nber.org/core/modules/system/css/components/tablesort.module.css?tduart517 B
www.nber.org/modules/contrib/paragraphs/css/paragraphs.unpublished.css?tduart362 B
www.nber.org/modules/custom/nber_user_auth/js/cookies.js?tduart1.2 KiB
www.nber.org/core/modules/system/css/components/clearfix.module.css?tduart578 B
www.nber.org/core/modules/system/css/components/nowrap.module.css?tduart389 B
www.nber.org/core/modules/system/css/components/details.module.css?tduart321 B
/core/modules/system/css/components/container-inline.modu...439 B
www.nber.org/core/modules/system/css/components/align.module.css?tduart581 B
www.nber.org/core/modules/system/css/components/hidden.module.css?tduart937 B
www.nber.org/modules/custom/nber_charts/css/unemployment-graphic.css?tduart549 B
/core/modules/system/css/components/system-status-report-...435 B
www.nber.org/core/modules/system/css/components/system-status-counter.css?tduart561 B
/core/modules/system/css/components/system-status-report-...611 B
www.nber.org/core/modules/system/css/components/item-list.module.css?tduart513 B
www.nber.org/core/modules/system/css/components/resize.module.css?tduart376 B
www.nber.org/modules/contrib/sitewide_alert/css/sitewide_alert.css?tduart476 B
/core/modules/system/css/components/reset-appearance.modu...542 B
www.nber.org/core/modules/system/css/components/fieldgroup.module.css?tduart374 B
www.nber.org/core/modules/views/css/views.module.css?tduart492 B
www.nber.org/core/modules/system/css/components/js.module.css?tduart591 B

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

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: 40 ms 41.0 KiB
URLTransfer SizeEst Savings
www.nber.org/themes/custom/nber/assets/build/css/nber-generated.css?tduart45.7 KiB41.0 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 359.5 KiB
URLTransfer SizeEst Savings
www.nber.org/themes/custom/nber/assets/build/js/libraries-generated.js?tduart272.3 KiB146.5 KiB
www.googletagmanager.com/gtag/js?id=G-3Y05NLKEBB&cx=c&gtm=4e64k0h2155.6 KiB63.5 KiB
www.googletagmanager.com/gtm.js?id=GTM-MVRPF7C143.1 KiB62.1 KiB
cdnjs.cloudflare.com/ajax/libs/d3/6.7.0/d3.min.js72.7 KiB54.6 KiB
www.nber.org/themes/custom/nber/assets/build/js/index-generated.js?tduart51.1 KiB32.8 KiB

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 5.6 KiB
URLTransfer SizeEst Savings
www.nber.org/core/misc/drupal.js?v=10.4.97.1 KiB5.6 KiB

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

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: 237 ms
URLTime Spent
nber.org/237 ms
www.nber.org/0.0 ms
●Time to Interactive 2.3 s
●Layout shift culprits
●Optimize DOM size
●LCP breakdown
●Modern HTTP
●Optimize viewport for mobile
●Max Potential First Input Delay 60 ms
●Minify CSS
●Avoids enormous network payloads Total size was 1,434 KiB
●User Timing marks and measures 5 user timings
●JavaScript execution time 0.2 s
●Minimizes main-thread work 0.8 s
●Avoid long main-thread tasks 1 long task found
●Avoid non-composited animations 4 animated elements 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 20 ms
●Tasks
●Diagnostics
●Metrics
●Screenshot Thumbnails
●Final Screenshot
●Script Treemap Data
●Resources Summary
●Initial server response time was short Root document took 260 ms
○INP breakdown
○LCP request discovery
○Avoid large layout shifts
91

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.

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
Latest from the NBER div.promo-grid__promos > div.promo-grid__multi-promo > div.page-subtitle > h3.page-subtitle__title

These are opportunities to improve keyboard navigation in your application.

Tables and lists

Screen readers have a specific way of announcing lists. Ensuring proper list structure aids screen reader output. Learn more about proper list structure.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
Economic Measurement Research Institute PROJECT Coordinating Center on the Econ… section.promo-grid > div.promo-grid__promos > div.book-list > ul.book-list__list
2025, 17th Annual Feldstein Lecture, N. Gregory Mankiw," The Fiscal Future" FEL… section.promo-grid > div.promo-grid__promos > div.book-list > ul.book-list__list

These are opportunities to improve the experience of reading tabular or list data using assistive technology, like a screen reader.

Best practices

Touch targets with sufficient size and spacing help users who may have difficulty targeting small controls to activate the targets. Learn more about touch targets.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
617-868-3900 div#block-footercontact > div.footer__contact-address > p > a
info@nber.org div#block-footercontact > div.footer__contact-address > p > a
webaccessibility@nber.org div#block-footercontact > div.footer__contact-address > p > a
Accessibility Policy nav.footer-legal > ul > li > a
Diversity Policy nav.footer-legal > ul > li > a
Privacy Policy nav.footer-legal > ul > li > a

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
Read the research here div > div.digest-card > div.digest-card__summary > a
Read the research here div > div.digest-card > div.digest-card__summary > a
Read the research here div > div.digest-card > div.digest-card__summary > a
Read the research here div > div.digest-card > div.digest-card__summary > a
Read the research here div > div.digest-card > div.digest-card__summary > a
○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
●Image elements have `[alt]` attributes
●Form elements have associated labels
●`[user-scalable="no"]` is not used in the `<meta name="viewport">` element and the `[maximum-scale]` attribute is not less than 5.
●ARIA attributes are used as specified for the element's role
●`[aria-hidden="true"]` elements do not contain focusable descendents
●Elements use only permitted ARIA attributes
●Background and foreground colors have a sufficient contrast ratio
●Document has a `<title>` element
●`<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
●List items (`<li>`) are contained within `<ul>`, `<ol>` or `<menu>` parent elements
●No element has a `[tabindex]` value greater than 0
●Document has a main landmark.
●Deprecated ARIA roles were not used
●Image elements do not have `[alt]` attributes that are redundant text.
●Identical links have the same purpose.
○`[accesskey]` values are unique
○`button`, `link`, and `menuitem` elements have accessible names
○Elements with `role="dialog"` or `role="alertdialog"` have accessible names.
○ARIA input fields have accessible names
○ARIA `meter` elements have accessible names
○ARIA `progressbar` elements have accessible names
○Elements with an ARIA `[role]` that require children to contain a specific `[role]` have all required children.
○`[role]`s are contained by their required parent element
○Elements with the `role=text` attribute do not have focusable descendents.
○ARIA toggle fields have accessible names
○ARIA `tooltip` elements have accessible names
○ARIA `treeitem` elements have accessible names
○The page contains a heading, skip link, or landmark region
○`<dl>`'s contain only properly-ordered `<dt>` and `<dd>` groups, `<script>`, `<template>` or `<div>` elements.
○Definition list items are wrapped in `<dl>` elements
○ARIA IDs are unique
○No form fields have multiple labels
○`<frame>` or `<iframe>` elements have a title
○`<html>` element has an `[xml:lang]` attribute with the same base language as the `[lang]` attribute.
○Input buttons have discernible text.
○`<input type="image">` elements have `[alt]` text
○The document does not use `<meta http-equiv="refresh">`
○`<object>` elements have alternate text
○Select elements have associated label elements.
○Skip links are focusable.
○Cells in a `<table>` element that use the `[headers]` attribute refer to table cells within the same table.
○`<th>` elements and elements with `[role="columnheader"/"rowheader"]` have data cells they describe.
○`[lang]` attributes have a valid value
○`<video>` elements contain a `<track>` element with `[kind="captions"]`
○Tables have different content in the summary attribute and `<caption>`.
○All heading elements contain content.
○Uses ARIA roles only on compatible elements
○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
cdnjs.cloudflare.com/ajax/libs/d3/6.7.0/d3.min.js line 1, col 15113
Error: <path> attribute d: Expected number, "…3.5146590073207,NaN,1143.9174752…".
●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 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
100

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.

○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
●Image elements have `[alt]` attributes
●Document has a valid `hreflang`
●Document has a valid `rel=canonical`

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