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Harvard Study Do Display Ads Influence Search

Online marketing channels have a tendency to influence each other, but to what degree and with what implications has always been something of a mystery. A purchase is a core metric but when it comes to Display and Search working together it is hard to know who is doing what. For example, we can’t tell if a purchase is the result of a visitor seeing a display ad and purchasing or seeing a display ad and later performing a search and purchasing. The Harvard Business School conducted a study investigating whether display ads influence search.

There was little research done prior to this study. An initial study by Papadimitrou et al in 2012 found that exposure to a display ad increases the number of relevant search queries by 5-25%, thus proving that there was some kind of interaction between the two.

The Harvard Business School study went even further – and the results are compelling. In brief:

Impact: Display ads have a significant impact on search queries, clicks on searches and thus purchases.

Timelag: However, they also found that the impact on search queries did not happen instantly. The initial increase in display impressions does not generate immediate search queries, it took effect after  approximately two to four weeks.

Sustained activity: Another important finding is that the increase in search activity came after a sustained increase in display activity for a period of time, not a ‘one off’ burst.

Search doesn’t impact on display: Well, it makes sense to ask if it works the other way around? No, search advertising activity did not lead to an increase in clicks on display ads!

Problems with metrics like CPA

The Harvard study concluded that simple metrics commonly used to measure online activity like CPA may not accurately measure the effectiveness of campaigns. The reason for this is that these metrics are static and ignore attribution (how visitors may be more likely to search for a product after seeing a display ad and then buying) as well as the dynamic effects of display (the time lag between impressions and resulting increase in search queries).

At iProspect we are seeing much that confirms these findings. Display is an exciting field and is poised for game-changing advances in technology, however, it remains to be seen how the results of studies like this will be incorporated into tracking online performance and how we will be using them at iProspect.