Do first impressions work?
In the online world there are a wide variety of ways a prospect can come across our products and services. Figuring out which impression(s) are involved in a transaction should be reasonably straight-forward to figure out (at least logically.) Unfortunately, without some creative manipulation of the data it seems that the ad serving community has taken a page out of the accounting handbook. Raw data from MediaPlex uses a "Last Impression or Final Observation" rule. Interesting events, like orders, are associated with the most recent action, which may be a click-thru or a view-thru. So analyzing the impact of total impressions, or their sequence, becomes significantly restricted.
When I request raw data feeds from vendors, I expect to get the raw data -- not some set of low level business rules.