Help me to correlate Alexa Traffic Rank and unique visitors

[Pidea]

If you're like me you probably want to work how many visitors your competitors are getting. Of course they're not going to tell you so you need to find it elsewhere.

The trouble is that this info isn't available although Hitwise comes close, but considering the price it ought to.

So what to do ?

I've been looking at mine and my competitors Alexa Traffic Rank values but it's very difficult to estimate the number of unique visitors from this because the relationship between the number of visitors and the Alexa Rank is very non-linear.

I know that Alexa is skewed to Internet Explorer users and isn't perfect but if enough people shared (anonymously) there 3 month absolute unique visitors number, their 3 month Alexa traffic rank and also the percentage of users using IE then a relationship could be determined.

There will of course be errors but with enough people these will be reduced.

If you want to help out with this project, please post your values below. Once there's enough data I'll fit a curve through the points and will post the corresponding equation which'll allow you to estimate the number of visitors for any given Alexa rank.

To ensure that the results are as meaningful as possible, can you only submit sites where you're tracking visitors using Google Analytics ?

Here's the methodology I used:

1. Visit each of your sites and make sure that it has an Alexa rank otherwise the rest of this will be a waste of time ! Note down the Alexa rank shown OR get it from Alexa direct but grab the 3 month average value.

2. In Google Analytics, change the date range so that it covers a 3 month period. eg 12/16/2008 - 03/16/2009, click apply

3. Click Visitors and note down the value of the Absolute unique visitors shown

4. Click Browser Capabilities

5. Click Browsers and note down the Internet Explorer market share in percent

6. Post the values in the format Alexa / Absolute Uniques / IE share

Here are the values from my sites

3mth Alexa average / 3mth Absolute unique visitors / 3mth IE market share

859958 / 24,058 / 58.75
1100334 / 13,496 / 59.45
2845175 / 2,172 / 56.49
8161968 / 227 / 57.86
8677221 / 614 / 68.51
8677251 / 173 / 63.02

Remember, once there's enough data I'll post a spreadsheet containing the data points and a equation that you can use to estimate the unique visitor count.

And before anyone says 'But Alexa is crap' I know that Alexa isn't perfect but it's the most established of the various freely available traffic ranking tools which is why I've chosen to use it for this exercise.

Something similar to this has been done before but getting the info out again is difficult - I want to make it into a simple function that anyone can use by simply plugging in a value from Alexa. Here's the other version:

Correlation between Alexa and visitors

Cheers

Phil

[leofixer]

I have one blog that has not much traffic at all but alexa rank is pretty high, how?
This domain has 50 subdomains and each one of them has his own traffic so alexa considering their traffic as it is going to the main domain.
Tricky

[martinlock]

Alexa rankings can't be the sole determinants of measuring a sites importance and popularity as the rankings do not take into account all the browser types like Windows Vista etc.