• by Joe Mandese  @mp_joemandese, May 15, 2015

Whenever two audience measurement services operate in the same media marketplace it is not unusual for them to produce different tallies, but normally those differences relate to the consumer audience estimates they report, not the number of customers using them. But in the battle between digital ratings services comScore and Nielsen, the primary dispute appears to be the number of advertisers they have.

In a report sent to investors this morning, Wall Street analyst Brian Wieser says both companies’ claims of dominance are likely specious and irrelevant. Citing recent claims by comScore that 25 of the top 25 advertisers currently use its online audience ratings vs. Nielsen’s claim that 20 of the top 25 advertisers use its version, Wieser says something didn’t add up, so his team at Pivotal Research Group did some research of its own, reaching out to “several of our industry contacts to get to the bottom of the “dueling” claims by the online measurement services.

“We found several factors which help explain how both claims can be true,” Wieser wrote, citing:

• Video vs. Display. Both Digital Ad Ratings and vCE measure display and video ad products. It is not necessarily the case that a marketer will use the same campaign measurement service for both kinds of media.

• Countries of Use. Marketers may prefer to use one product in one country and the other product in another country.

• Testing Vs. Active Use. Marketers may choose to test one product alongside the other or may choose to run all campaigns on a different measurement system vs. one they have historically used.

• Agency Bought Vs. Marketer Bought. Inventory bought by an agency on behalf of a marketer might use one service, while inventory bought by the marketer directly might use the other.

• Publisher Access / Guarantee Issues. Some publishers will work with one of comScore or Nielsen, but not the other. Others might allow use of both platforms, but only guarantee audience delivery on one, and not the other. A marketer must then decide how important it is to buy from a given publisher, and then to the extent that some form of demographic measurement is better than none, they may deviate from using their preferred service.

Wieser concludes that the net result of the factors indicates “the claims made by both companies are made somewhat irrelevant, unless we know additional specific parameters.” But he concludes by suggesting that Nielsen is in fact the dominant service for large brand marketers: “Our ongoing checks with marketers convey to us that Nielsen’s campaign measurement tools continue to dominate the preferences of the largest brands, likely capturing a greater share of spending. There is some degree of competition around display, but video is the battlefield that matters more, as it drives the strategic value underpinning Nielsen’s overall media measurement franchise.”