From version 8 of the Safari web browser the navigation timing API is supported. This marks the last of the major browsers to include support. It will also see navigation timing supported in iOS.
This is a significant step forward for real user monitoring and measurement. It means that (once everyone has upgraded) we could have 33% more page speed data to work with. If we separate out mobile users, then Safari is used for about half of mobile web browsing. This means we see a 100% increase in data sample points within the mobile/tablet segment.
For the first time we have the potential to get a lot of insight into exactly how fast (or slow) our websites and products are on devices using Safari. Together with existing support in Chrome for mobile, the vast majority of mobile web browsing will now provide timing data.
How to prepare
Google Analytics only records the navigation timing information for 1% of pageviews by default. This isn’t going to paint you much of a picture.
You should increase the sample rate to 100%. It’s pretty safe and simple to do this. I’ve explained how to make this change in another blog post.
Make sure you make this change as soon as possible. Ideally before Apple releases Safari 8 – which will be the 17th September 2014 when iOS 8 becomes available for download.
How to use the data
The navigation timing data can uncover problem pages on your website. It can help you analyse the performance of critical pages. Previously this data had a massive hole in it due to the absence of Safari support. This meant that many iPhone, iPad and Apple users were missing from the data.
Once Safari 8 is released, keep your eye on the browser report in Google Analytics. Here’s a report you can use where I’ve added browser version as a second dimension and then filtered by “Safari”. The larger chunk of the pie that Safari 8 has, the more complete your data is likely to be.
You can use the page timing data to see what problem pages you have – identify pages that are taking too long to load. Segmenting your analytics data by mobile device, tablet, desktop, browser and territory will help produce a better picture. Read this guide to learn more about what you can do: How fast is your website on mobile devices.
— James Royal-Lawson (@beantin) September 9, 2014