What is a 404 error
A 404 error is a standard HTTP response when a request is made to a server that it can't find. A typical example of this is when you try seeing a page that doesn't exist, let us say: http://www.google.com/yourname you get a 404 error page.
Users will sometimes end up in a 404 page either because they are following a broken link or by typing the wrong URL. Because you don't want to lose those users it is best practice to detect these errors and react to them.
Note: If the page has existed, but no longer exists and won't exist in the nearby future you might want to ask your dev to issue a 410 (not coming back) or a 310 (permanent redirect). Google normally waits 24 hours after it gets a 404 to check a page a again and see if it was a temporary glitch.
One of the top things to do on your digital marketing checklist should be tracking events to see if you are reaching your goals. Normally digital marketers use tools like Google Analytics, KISS metrics, Mixpanel or similar.
Ideally you will have added the tracking code to all your pages, so that when it comes the time to track a specific metric/event you don't have to go back to the dev team and ask them to implement yet another code snippet in another page.
Tip: A good tool that helps to avoid this is Google Tag Manager.
The quickest way of detecting 404 errors for a marketer that is already tracking all pages is simply tracking pageviews of a certain page (ex: 404.html) or in case you are not redirecting to any specific page, but just printing an error page you can try tracking by page's title (ex: "error page", "The page you were looking for doesn't exist (404)", ...).
Example of a typical error page:
So how do you detect this? For illustration purposes I am going to use Google Analytics, but in theory you should be able to use any other tools.
Lets start by creating a custom report:
1. Go to the view you want to get the data from and click on the Customization tab.
2. Click New Report.
3. Set it up as below (example tracking the above title "the page you were looking for doesn't exist(404)).
Now you have a custom report that shows you how many Pageviews and Unique Visitors that have seen 404 pages. It also shows you what was the page they came from (in case the previous page was the referer it will show entrance).
Now that you have your report set you can either send it via email to the dev team every week/month or, if you don't want to bug them every single week/month you can set a custom alert to track big changes in 404 visualizations.
Go to the view you want to create an alert:
Click the create new alert button
Apply a daily alert when the number of 404's increases more than expected
Just keep an eye on your alert emails and the custom report or Google Webmaster tools to see more information. Eventually if your devs/designers don't have time to improve your current default error page one, try using Google's widget for 404 pages (see below section).
You might also want to read:
- Make your webpages more useful
- Create a custom 404 page
- What is a HTTP 404
- Creative 404 pages
- Matt Cutts comments 404 vs 410