Report Summary

  • 26

    Performance

    Renders faster than
    46% of other websites

  • 98

    Accessibility

    Visual factors better than
    that of 96% of websites

  • 67

    Best Practices

    More advanced features
    available than in
    34% of websites

  • 93

    SEO

    Google-friendlier than
    88% of websites

nih.gov

National Institutes of Health (NIH) | Turning Discovery Into Health

Page Load Speed

22.3 sec in total

First Response

67 ms

Resources Loaded

12.1 sec

Page Rendered

10.1 sec

nih.gov screenshot

About Website

Visit nih.gov now to see the best up-to-date NIH content for China and also check out these interesting facts you probably never knew about nih.gov

Official website of the National Institutes of Health (NIH). NIH is one of the world's foremost medical research centers. An agency of the U.S. Department of Health and Human Services, the NIH is...

Visit nih.gov

Key Findings

We analyzed Nih.gov page load time and found that the first response time was 67 ms and then it took 22.2 sec to load all DOM resources and completely render a web page. This is an excellent result, as only a small number of websites can load faster.

Performance Metrics

nih.gov performance score

26

Measured Metrics

name

value

score

weighting

FCP (First Contentful Paint)

Value4.1 s

22/100

10%

LCP (Largest Contentful Paint)

Value6.0 s

13/100

25%

SI (Speed Index)

Value4.7 s

69/100

10%

TBT (Total Blocking Time)

Value930 ms

30/100

30%

CLS (Cumulative Layout Shift)

Value1.105

1/100

15%

TTI (Time to Interactive)

Value8.0 s

43/100

10%

Network Requests Diagram

nih.gov

67 ms

www.nih.gov

524 ms

Universal-Federated-Analytics-Min.1.0.js

143 ms

css_mtppzd8_PFstl_yJg9eSCqHm2C-vo2-O3ZRK8QVn30M.css

448 ms

css__mIWP9gcStq74isjZVoAAsiih8VXwJoN75Nyw_BXrj0.css

603 ms

Our browser made a total of 57 requests to load all elements on the main page. We found that 77% of them (44 requests) were addressed to the original Nih.gov, 7% (4 requests) were made to Search.usa.gov and 5% (3 requests) were made to Google-analytics.com. The less responsive or slowest element that took the longest time to load (4.7 sec) relates to the external source Stats.g.doubleclick.net.

Page Optimization Overview & Recommendations

Page size can be reduced by 1.4 MB (34%)

Content Size

4.0 MB

After Optimization

2.7 MB

In fact, the total size of Nih.gov main page is 4.0 MB. This result falls beyond the top 1M of websites and identifies a large and not optimized web page that may take ages to load. 60% of websites need less resources to load. Images take 2.3 MB which makes up the majority of the site volume.

HTML Optimization

-81%

Potential reduce by 59.9 kB

  • Original 74.1 kB
  • After minification 71.0 kB
  • After compression 14.3 kB

HTML content can be minified and compressed by a website’s server. The most efficient way is to compress content using GZIP which reduces data amount travelling through the network between server and browser. HTML code on this page is well minified. It is highly recommended that content of this web page should be compressed using GZIP, as it can save up to 59.9 kB or 81% of the original size.

Image Optimization

-2%

Potential reduce by 52.7 kB

  • Original 2.3 MB
  • After minification 2.2 MB

Image size optimization can help to speed up a website loading time. The chart above shows the difference between the size before and after optimization. NIH images are well optimized though.

JavaScript Optimization

-67%

Potential reduce by 712.0 kB

  • Original 1.1 MB
  • After minification 1.0 MB
  • After compression 343.9 kB

It’s better to minify JavaScript in order to improve website performance. The diagram shows the current total size of all JavaScript files against the prospective JavaScript size after its minification and compression. It is highly recommended that all JavaScript files should be compressed and minified as it can save up to 712.0 kB or 67% of the original size.

CSS Optimization

-86%

Potential reduce by 558.2 kB

  • Original 647.5 kB
  • After minification 626.6 kB
  • After compression 89.3 kB

CSS files minification is very important to reduce a web page rendering time. The faster CSS files can load, the earlier a page can be rendered. Nih.gov needs all CSS files to be minified and compressed as it can save up to 558.2 kB or 86% of the original size.

Requests Breakdown

Number of requests can be reduced by 22 (42%)

Requests Now

53

After Optimization

31

The browser has sent 53 CSS, Javascripts, AJAX and image requests in order to completely render the main page of NIH. We recommend that multiple CSS and JavaScript files should be merged into one by each type, as it can help reduce assets requests from 15 to 1 for JavaScripts and from 9 to 1 for CSS and as a result speed up the page load time.

Accessibility Review

nih.gov accessibility score

98

Accessibility Issues

Navigation

These are opportunities to improve keyboard navigation in your application.

Impact

Issue

High

Heading elements are not in a sequentially-descending order

Best Practices

nih.gov best practices score

67

Areas of Improvement

Trust and Safety

Impact

Issue

High

Does not use HTTPS

High

Includes front-end JavaScript libraries with known security vulnerabilities

Low

Ensure CSP is effective against XSS attacks

User Experience

Impact

Issue

High

Serves images with low resolution

General

Impact

Issue

Low

Detected JavaScript libraries

High

Page has valid source maps

High

Issues were logged in the Issues panel in Chrome Devtools

SEO Factors

nih.gov SEO score

93

Search Engine Optimization Advices

Crawling and Indexing

To appear in search results, crawlers need access to your app.

Impact

Issue

High

Links are not crawlable

Mobile Friendly

Make sure your pages are mobile friendly so users don’t have to pinch or zoom in order to read the content pages. [Learn more](https://developers.google.com/search/mobile-sites/).

Impact

Issue

High

Document uses legible font sizes

Language and Encoding

  • Language Detected

    EN

  • Language Claimed

    EN

  • Encoding

    UTF-8

Language claimed in HTML meta tag should match the language actually used on the web page. Otherwise Nih.gov can be misinterpreted by Google and other search engines. Our service has detected that English is used on the page, and it matches the claimed language. Our system also found out that Nih.gov main page’s claimed encoding is utf-8. Use of this encoding format is the best practice as the main page visitors from all over the world won’t have any issues with symbol transcription.

Social Sharing Optimization

Open Graph data is detected on the main page of NIH. This is the best way to make the web page social media friendly. Here is how it looks like on Facebook: