Victorian Auditor-General’s Office

The Index


Google Lighthouse Performance

The Google Lighthouse performance score is a metric that measures the speed and performance of a website. It’s an overall score that ranges from 0 to 100 and is generated based on a number of different performance metrics, such as the time it takes for a website to load, the time it takes for a website to become interactive, the size of the resources used by the website, and other factors that impact the user experience.

A high performance score in Google Lighthouse indicates that a website is fast and responsive, which can lead to a better user experience and improved search engine rankings. On the other hand, a low performance score can indicate that a website is slow and unresponsive, and can negatively impact the user experience.

Mobile Performance
Desktop Performance

Core Web Vitals

Core Web Vitals are a set of specific factors that Google considers important in a webpage’s overall user experience. Core Web Vitals are made up of three specific page speed and user interaction measurements: Largest Contentful PaintFirst Input Delay, and Cumulative Layout Shift.

Largest Contentful Paint6.7 s2.0 s< 2.5 s
First Input Delay170 ms30 ms< 100ms
Cumulative Layout Shift00.001 0.1


Optimise images

By optimising the following images, roughly 5 MB could be removed from the transfer size, about 53%. This would reduce the CO2 generated per page load from 2.69g grams to 1.28 grams.

Images should be optimised for the web for several reasons:

  1. Reduced file size: Optimizing images can result in a smaller file size, which can help to reduce the amount of data that needs to be downloaded. This can lead to faster page load times and improved performance.
  2. Improved user experience: Optimising images can help to improve the overall user experience, as pages with optimised images load faster and are more responsive.
  3. Lower emissions: Optimising images can help to reduce the emissions associated with data transfer, as less data needs to be transmitted over the network.
  4. Better accessibility: Optimising images can make them more accessible to users with slower connections or limited data plans.
Native%20forests_thumb.png 742 KB 7% 498 KB
FA-LG-thumbnail.png 691 KB 7% 447 KB
FA-LG-thumbnail_0.png 691 KB 7% 447 KB
Environment-and-natural-resources.png 673 KB 6% 428 KB
BP4_thumb.png 669 KB 6% 425 KB
Annual%20Report%202021-22%20196853743%201000x1000.png 648 KB 6% 404 KB
Regulating-private-pool-and-spa-safety-thumbnail.png 626 KB 6% 382 KB
SCStation.jpg 597 KB 6% 353 KB
AFR2021%E2%80%9322%20thumb.png 591 KB 6% 346 KB
AFR2021%E2%80%9322%20thumb_0.png 591 KB 6% 346 KB
Railway-assets-web-thumbnail.png 572 KB 5% 328 KB
Business-and-economic-development.png 499 KB 5% 255 KB
Education.png 457 KB 4% 212 KB
Transport.png 410 KB 4% 165 KB
Justice.png 394 KB 4% 150 KB
Health-services.png 362 KB 3% 118 KB
Fair-presentation-of-service-delivery-performance-2022-thumbnail.png 275 KB 3% 31 KB

Remove third party font files

Font files should be loaded from the same hosting as the website because

  1. Increased loading time: Third-party sub-resources, such as scripts, fonts, or images, need to be downloaded from a separate server before they can be displayed on the website. This can increase the overall loading time of the page, leading to a slower user experience.
  2. Dependence on external servers: The loading of third-party subresources is dependent on the availability and performance of the external servers that host them. If these servers are slow or unavailable, it can result in slow page loading times or even errors.
  3. Increased risk of security threats: Third-party subresources can introduce security risks to a website, as they can contain malicious code or be used to track user activity.

First Contentful Paint

First Contentful Paint (FCP) is a performance metric that measures the time it takes for the first piece of content to be rendered on the screen when a user navigates to a web page. This content can be any visual element on the page, such as text, images, or a background color.

FCP is important because it directly affects the perceived speed of a website, and can impact user engagement and conversion rates. A faster FCP can lead to a better user experience and improved performance.

Here are a few ways you can optimise your FCP:

  1. Optimise images: Large, unoptimised images can slow down a page’s FCP. You can optimise images by compressing them, reducing their dimensions, and choosing the right format for each image.
  2. Minimise HTTP requests: Each resource requested by a web page, such as images, scripts, and stylesheets, requires a separate HTTP request. Minimising the number of HTTP requests can help to reduce the time it takes for a page to render.
  3. Prioritize critical content: Prioritizing critical content, such as above-the-fold content, can help to ensure that users see something on the screen quickly, even if the rest of the page is still loading.
  4. Reduce server response time: A slow server response time can significantly impact FCP. Optimizing server-side code and server settings can help to reduce response times and improve FCP.
  5. Use a performance monitoring tool: There are many tools available that can help you monitor your website’s performance, including FCP. These tools can help you identify performance issues and track your progress as you implement optimizations.
Timing2.5 s0.7 s

Largest Contentful Paint

Timing6.7 s2.0 s

Total Blocking Time

Timing380 ms0 ms

Speed Index

Timing15.9 s4.2 s

Time to Interactive

Timing29.3 s0.7 s

Max Potential First Input Delay

Timing170 ms30 ms

First Meaningful Paint

Timing2.5 s0.7 s

Eliminate render-blocking resources

InsightPotential savings of 1,440 msPotential savings of 440 ms

Properly size images

InsightPotential savings of 93 KiBPotential savings of 4,569 KiB

Defer offscreen images

InsightPotential savings of 1,204 KiB

Reduce unused JavaScript

InsightPotential savings of 351 KiBPotential savings of 350 KiB

Efficiently encode images

InsightPotential savings of 23 KiBPotential savings of 23 KiB

Serve images in next-gen formats

InsightPotential savings of 6,841 KiBPotential savings of 8,459 KiB

Reduce initial server response time

InsightRoot document took 1,410 msRoot document took 1,430 ms

Preload Largest Contentful Paint image

InsightPotential savings of 330 ms

Avoid enormous network payloads

InsightTotal size was 8,694 KiBTotal size was 10,440 KiB

Serve static assets with an efficient cache policy

Insight48 resources found48 resources found

Avoids an excessive DOM size

Insight559 elements559 elements

JavaScript execution time

Timing1.7 s0.2 s

Minimizes main-thread work

Timing3.0 s0.7 s

Ensure text remains visible during webfont load


Image elements do not have explicit width and height