Data discrepancy % in Google Analytics
My small business(ecom) runs with Google Analytics on web side and have another tracker on backend to collect my transaction numbers. I often rely on GA to see the behaviour of users along with my ecom numbers. However, my transaction data on GA is not matching/nearest to my ecom numbers. The diffrence percentile varies day by day or month on month. I can say an average of 7% data difference from my GA to backend data.
Can I guess that this 7% is a product limitation by GA? if not, what is the actual data loss by GA?
Re: Data discrepancy % in Google Analytics[ Edited ]
August 2016 - last edited August 2016
I'm not a an expert but anyway I want to share my experience.
Even if all the configuration of GA its OK there will be always a chance that your data with your own tracker will not match GA.
The RAW data of GA its not available for anyone, the metrics we see are the result of pre-aggregated tables. For make this calculations GA use some algorithms that are very accurate but not exact.
For example, for users metrics, GA must count the number of different "ID" that are present in the time interval you are looking. For this the most obvious process its to compare one by one all the ID with the other "ID" to count the number of different "ID" or users are present. For this (even ordering all the IDs first) the server takes a lot of time. For that reason GA occupies a algorithm for estimate the number of different users.
Anyway for a 7% difference I think its too much and maybe a there is something to reconfigure in the Analytics configuration. Check if you tracker uses the same method that GA to count users: cookies.
(I'm not english native speaker)