Difference seen between Data Warehouse Report and Analysis Workspace Reports

One of the differences between data warehouse and workspace is that data warehouse doesn't low traffic bucket dimension items. If you have a dimension in workspace that exceeds the unique value threshold in a given month, the rest of the items will be put in a 'low traffic bucket', but in data warehouse all values will be shown on their own line, regardless of how many there are. 

The persistence shouldn't be changing between data warehouse and workspace though, if you're using the same dimensions/metrics.

Another potential issue you might be seeing depends on what metrics you are using, and if any of the field contain multiple values (like lists).

So for the first think I mentioned, if you are exporting Unique Visitors or Visits as your metric, and you are looking at the totals, they won't be deduplicated in the Data Warehouse Export. So if you try to total the up, you will be overcounting.

Example:

Visit 1:

• Page A
• Page B
• Page A

Visit 2

• Page A
• Page C

In the Workspace, you will end up with:

The total Visits being "2" not (2+1+1 = 4) and Unique Visitors being "1" (and not 1+1+1 = 3)

In the Data Warehouse, you will just get:

And if you are exporting anything like a list that has multiple items

Example:

Page A

• List1 = "value1,value2,value3"

The Data Warehouse will export:

There will be a row for each unique combination of data (i.e. 3 rows for the same page view if there are 3 items, 20 rows for the same page view if there are 20 items in the list)... 

You should review what dimensions / metrics you are including, and make sure that you understand where duplications can occur.