How are Alexa Ranks
measured?
According to the official Alexa website’s Our Data page, the
rank is calculated using a ‘combination’ of the estimated average daily unique
visitors to the site and the estimated number of pageviews on the site over the
past 3 months – with the site with the highest combination of unique visitors
and pageviews being ranked as #1. The data is collected from a subset of
internet users using one of 25,000 browser extensions for either Google Chrome,
Firefox, and/or Internet Explorer. An algorithm then ‘corrects’ for various
potential biases and attempts to compensate for visitors who might not be in
Alexa’s measurement panel (a factor it historically hasn’t always tried to
accommodate for) and normalizes the data based on the geographical location of
visitors.
How can I view a
website’s Alexa Rank?
At least this part is straightforward: simply go to the
official Alexa website, type in your full domain name and hit return! What’s
more, scrolling down the results page reveals no end of other interesting
metrics, such as Bounce Rate, Daily Pageviews per Visitor, Daily Time on Site
and the Percentage of visits from Search, as well as various Demographics, a
list of sites that link and even page speed/load times! All of which should
probably be taken with a pinch of salt…
What does the Alexa
Rank mean?
The general consensus seems to be a reluctant admittance by
most (certainly not all) that there does indeed appear to be a very general –
rough – correlation (seemingly with a LOT of outlying data points) between a
site’s Alexa Rank and traffic for well-established websites that receive over
and above a certain level of traffic: i.e. for relatively popular sites with
Alexa Ranks of less than somewhere in the region of about 50,000 to 100,000 –
to their credit, Alexa does actually state on their website that ‘traffic
rankings of 100,000 and above should be regarded as [very?] rough estimates‘
and that conversely ‘the closer a site gets to #1, the more accurate traffic
rankings become‘. Anything higher than this 100,000 waypoint and everyone I’ve
ever spoken to on the subject (I hangout in somewhat geeky circles) seems to
pretty much laugh it off as a metric that can, nine times out of ten, be almost
completely ignored.
Why don’t people tend
to trust it?
It seems that a lot of people/webmasters with access to
reliable web analytics data (the most popular being provided by Google
Analytics of course) for more than one website often report seeing web-traffic
trends and statistics that appear to be completely out of line with the
corresponding Alexa Rank for each site. Unfortunately, you’ve only got to
Google something like ‘Is Alexa Rank Accurate?’ to find such reports – not
good! Although, in all fairness, quite a few of these reports are for websites
with quite high Alexa Ranks – i.e. often way in excess of the 100,000 mark.
The real kicker though, seems to be two-fold: 1) Alexa
aren’t able to gather their data from everybody (they obviously simply don’t
have access to everybody’s browsing habits) – they can only gather data from a
subset of a few million users via certain browser extensions (as previously
mentioned) – something common sense suggests will almost certainly skew the
data right from the get-go (since the average user presumably arguably isn’t
likely to have installed any such browser extensions) and 2) rather than
address such concerns head on and be completely open about exactly how this
particular problem is accounted for, i.e. by being more open about exactly how
the underlying data is collected and used to calculate the rank, Alexa seem to
(as far as my admittedly somewhat limited research goes) be less than 100%
transparent on the matter, simply stating that Alexa Rank ‘is calculated using
a combination of the estimated average daily unique visitors to the site and
the estimated number of pageviews on the site over the past 3 months’. Hmmmm….
Are Alexa Ranks
important?
For most site owners, ‘how a website is doing’ is of course
very important, however, when assessing your own website my advice would be to
simply stick with Google Analytics data rather than to go attributing any
significant meaning to your site’s Alexa Rank. When looking at competitor’s
sites however, by all means take a quick peek at their Alexa Rank for a very
rough idea of how popular their website is relative to yours (assuming the same
kinds of people visit both sites – thereby hopefully minimizing some of the
biases brought about by the significantly-less-than-perfect way in which Alexa
gather their data); however I definitely wouldn’t go thinking a particular
website gets more traffic than another merely on the basis that its Alexa Rank
happens to be only a few thousand lower – and if the website you’re interested
in happens to have a rank of anything even near the aforementioned 100,000
mark, it’s probably best not to go attributing any significant meaning to
comparing Alexa Ranks at all!
Conclusion
I personally hope that Alexa continues to work towards
really getting this particular metric up to scratch… because it sure would be
nice to stick a number on each and every website that would allow us to compare
and contrast them all with a decent level of accuracy! Unfortunately, it would
appear that they’ve still got quite a long way to go in order to regain the
industry’s faith in the matter!
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