If you’re running a small website and using Google Analytics, your site speed metrics graph might look empty. If you don’t get a lot of traffic there will be no samples to measure site performance. This is because the default sampling rate is only 1% (i.e. site speed metrics will only be collected for 1% of your visitors). This is plenty if your running a big site with tons of visitors per day, but if your running a smaller site this isn’t going to be good enough.

Luckily, Google Analytics allows you to change this setting. If you’re using Universal Analytics you can set the site speed sample rate when creating your tracker. In the example below I have set the tracker to sample 50% of my visitors by passing {'siteSpeedSampleRate': 50} in the create call.

<script type="text/javascript">
(i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),

ga('create', 'UA-XXXX-Y', {'siteSpeedSampleRate': 50});
ga('send', 'pageview');

After doing this I got a significant increase in the number of samples per day, allowing me to get a better idea of how my site was performing.