Over the years I've noticed as much as 20% of traffic (and transactions) missing out of Google Analytics. Whether or not they won't disclose it or they can't, I have no idea (the amount that gets chopped out seems to vary over my many sites)
They don't claim to be 100% accurate, and if you manage to grab ahold of someone privately, they'll tell you to consider GA as something to reflect trends, and not 100% of your site stats.
(Implied but not stated is "what do you want, it's free")
It is what it is.
Could this be "me"? I turn off GA via JS so no site I visit ever logs me in GA.
I don't doubt others also do this: GA has been historically slow to load, slugging down the actual page load, plus I do not want google-anything following me around nowadays. It's easy to turn off and NoScript turns it off by default.
If a report requires calculation on more than 250,000 visits, we select a statistically random sample of 250,000 visits and estimate the report results based on that data. This makes reports faster to load, and our testing indicates that the data returned is highly accurate.
To use the new report calculation control, click the new icon (square cube graphic) in the upper right of your report when you see a message that your report was generated with a percentage of your visits. Then you can drag the slider to your desired number of visits: we will automatically recalculate your report and remember this number for all reports until you log out.
Google has a history of not disclosing all traffic data since giving us 100% of it would allow us to deconstruct changes over time against changes made to our sites. I highly recommend using your own server log analyzers and building the reports you NEED to be competitive with.
>> I highly recommend using your own server log analyzers and building the reports you NEED to be competitive with.
Heh, the best log analyzer that I had ever used was Urchin which in turn became Google Analytics. It seems to be impossible to get it now (the license used to be included in one of my server packages).
Try Piwik. It's free, open source and does a solid job - lots of happy users.
I am going to try Piwik. Thanks for the recommendation!
I see now. thanks for replies. i will try Piwik
You get 100% of visitors, page views etc. For percentage data, like browser & OS, it calculates using a 'statistically random sample.' Probably to conserve processing time and make reports load faster.
Why do people still use Google Analytics when it's clearly evident they are not disclosing ALL the information that is coming out of your traffic (to you at least)?
I use Statcounter and couldn't be happier. No more feeding the evil Google, no more "(not provided)".
What amazes me most....is that GA does not provide IP addresses whatsoever.