Are there any reasons to not to set speed sample rate to 100 in Google Analytics?

Question

While searching for performance problems, I found out that we have several entries where our page load time is zero or extremly high (>150s).

After a short research I found out that this happens because of a combination of speed sample rate of 1% (default) and low visitor counts in specific times (at night/late hours). To get better data I want to set it to 100%.

Is there any reason to not to set the siteSpeedSampleRate to 100%?

I guess Google sets it to 1% because that might be enough for high traffic sites.

Answer 1

The reason why it is set so low is that sending the speed tracking beacons adds to the site load time and can cause performance issues. Sampling 1% of your users generally gives an accurate figure on site speed however if your traffic is so low that you are seeing extremely low or extremely high values try setting it higher. I would avoid setting it to 100% as this should not be necessary. Unfortunately it depends on your specific traffic patterns so would take some experimentation on your part. Try increasing it by 5% increments until you see accurate figures and then you will have the sampling rate that works for your site at this time. As your traffic increases you will be able to reduce the sampling rate until it is back down to 1%.