Referrer (originally misspelled referer: https://en.wikipedia.org/wiki/HTTP_referer#Etymology), can often be inaccurate when using this as a filter when analyzing traffic or marketing campaigns. Because this field is an optional part of the HTTP request, there can be several reasons why using this filter can produce inaccurate results.
One such reason is due to referrer hiding. With the increase in privacy concerns, many servers and browsers will not send the referrer data, or can even send false data. Additionally, browsers will not send the referrer field when they are redirected using the “Refresh” field.
Another reason is due to Secure (HTTPS) access. If the user connects from HTTPS to HTTP, this will also cause the referrer to not be sent. This is implemented to increase security for end users.
Also, some pages that use HTML5 can add attributes (rel=”noreferrer”) which will instruct the user agent to not send a referrer.
These are just some of the reasons why using referrer can be inaccurate. While they can be useful to see a general or overall view of where you're traffic is coming from, they might not be entirely correct.
So, how does one get more accurate data on where a user comes from?
In Woopra, we recommend the use of UTM tags when linking traffic to your site. If you are running a campaign, Woopra can use these UTM tags to automatically track campaigns and allow you to filter more accurately on the traffic to your site.
To get the most out of UTM tags and campaign tracking, please see our documentation on how you can set up UTM tags: https://docs.woopra.com/docs/campaign-tracking
Updated about 3 years ago