Difference between metrics in UI and API

[Hampus Brynolf]

I get quite big difference between the API and the UI in regards of visits and visitors.

The site is big, and I'm using filters as well as profiles (w filters). 

I understand that there will be a difference when the data is sampled, but also when not sampled I get big differences!

The filter used in the API, the UI and the profile is identical (filtering on a subfolder on pagePath).

See https://docs.google.com/spreadsheet/ccc?key=0Aqzq0UJQNY0XdG1DRFpaeWJveWhhdXZRemRlZ3pFb0E#gid=2 

Any ideas about the (BIG) differences?

Best regards,

//Hampus  

[chris@shufflepoint]

For comparisons it is best to create a custom report in GA.

[CE]

Likewise, I'm getting discrepencies between the API and web interface.

[Aaron Toledo]

You'll probably have to elaborate on exactly how you're filtering by pagepath in both the API and in your profile filter definition. I've occasionally seen similar errors but it usually comes down to a mistake in my original query. For the most part, I'm able to match up unsampled data in the accounts I look at. For example, if you do a regex match filter with the API against a pagepath, it will return pagepaths that match that expression (obviously). But, if you create a custom segment where pagepath contains a specific string, it's applied at the "visit" scope and you get all the data for any visit where that pagepath was part of the session. I know that example isn't exactly like your situation, but you it's an example of how you might get a different outcome from what seems like the same thing.