People comment about the fact that we check (and probably more importantly score) external links on the websites we audit.  So I thought a blog posting on our thoughts behind why we do this would be helpful.

When we "look" at a web page during an Audit, we run all of our checks on the page. We then check all of the links on the page.  If it's an external link we simply download the Base Page of the linked page and do two things - a) check that the link is working and b) check the performance.  We do this because these are links from your pages that people may click on and we consider that any link on one of your pages, whether it is an internal link to another page on your site or to one of your partner sites, is important - otherwise why link to it ?  It's also based on the premise that if people click on a link on one of your pages they are not necessarily going to go into any deep thought process about who's responsibility it is if that link fails or is horribly slow.  It's on your page and therefore it's YOUR fault.  Once they get onto another site's page it's much more obvious that it's someone else's site and any subsequent problems are theirs not yours.  Which is why we don't fully audit external pages but simply check the link to it and it's performance.

A typical view is "I can understand flagging external response errors such as 404s because we have a control over that - we either link or not".  Then surely this is equally true of a page who's performance is consistently awful - link or don't ? Like everything in Sitemorse we are attempting to report things that are useful to you.  A report that tells you what the 10 slowest items on your site are is undoubtedly a useful piece of information that you can decide whether or not to act upon.   (It isn't a subjective measure from our point of view, we're simply taking the 10 slowest items whilst making no judgement on them as to how slow they are.  They are just slower than everything else we tested during the audit.)  And whether it's an internal or external page, it's just the remedy that's different.  If it's a really important link that's always slow then there's not much to be done but it doesn't mean you shouldn't be made aware of it. 

Let's not confuse the scoring that we do with the value of the information that we provide.  We appreciate that people are focussed on how well they do in the Surveys and whether their scores are improving.  But let me put this in perspective,  When we are calculating the average response times and average download speeds from which we calculate the performance score we take the timings from every single GET request we issue as we traverse the site.  Let's say we issue an average of 10 GET requests per page and we audit 250 pages.  That's 2,500 GET requests.  One external link that is a bit slow won't shift the average speed figures by any significant amount and will have NO impact on the performance score for that audit run.  e.g. If the average response time across the 2,500 requests was 0.5 seconds it would need almost 10% (that's 250) of them to change to 1.5 seconds in order to change the average to .6 seconds.  So one, two or ten slow external links will make no difference to the score.

Another Blog posting on external links called "Broken links are broken links" is here http://blog.sitemorse.com/2008/06/broken-links-are-broken-links.html