Moving to "Viewable Impressions" Isn’t The Answer

The Sell-Sider"The Sell-Sider" is a column written by the sell-side of the digital media community.

Today's column is written by Tom Shields, Co-Founder and Chief Strategy Officer of Yieldex, an analytics tools provider for sell-side, yield optimization.

I am biased, I’ll admit it.  I wrote the first technical impression counting standards for the IAB in 1998.  And I think that trying to move the industry to "viewable impressions" is a bad idea, for three reasons: it won’t make any difference to marketing ROI, it doesn’t help bring dollars online, and it will be expensive and confusing to adopt.

Let’s start with the argument that using “viewable impressions” improves marketing ROI.  Measurement vendors trumpet “CTRs are higher!” for the marketer, while “CPMs will rise! for the publisher.  Let’s do a little math.  C3 Metrics claims that CTRs are understated by 179% because so many ads aren’t in view.  Wow – CTRs will double!  Except, publishers will charge double the CPM for “viewable impressions”, so the CPC (and ROI) is actually the same.  On the publisher side, Magid Abraham presented to the IAB (PDF) an example of 35m premium impressions selling at $5 CPM netting $175k to the publisher.  However, only 75% of those are “viewable” according to ComScore, so the eCPM is “actually” $6.67.  Wow – CPMs will rise!  Except that the publisher can only charge that higher CPM (CPV, actually) for “viewable impressions”, so their revenue stays the same.   And somebody has to pay the measurement vendor.  This is progress?

These “increases” may improve the perception of online advertising, but marketers and publishers are smart enough to know they don’t make any real difference.  Yes, the current impression standard is flawed in many ways, but we have over a decade of experience in setting rate cards, negotiating deals, and measuring results with it.  A new standard will have new as-yet-unknown flaws.  More importantly, it means creating new rate cards for CPV, and then redefining CTR (should it be VCTR?) with viewable impression as the denominator, so people don’t compare apples and oranges when looking at historical data.  The cynic in me says that this apples/oranges comparison is the main reason this idea is getting traction, but I can’t imagine anyone I know falling for that.  Other cynical reasons for the excitement may be that many agencies see this new metric as just the ticket to demonstrate to their clients that they “get” digital, and a few technology vendors see this as their path to revenue.  But in my view, this metric just adds another tax without creating any real value.

The real challenges we need to solve are laid out in the other 4 principles of Making Measurement Make Sense: rationalizing measurement across media, understanding online’s contribution to brand building, and generally making it easier to spend big budgets online and get ROI that makes sense.  Let's focus our efforts on these challenges, so we can grow the market to $200 billion for everyone.

Follow Tom Shields (@tshields), Yieldex (@yieldex) and ( on Twitter.


  1. Tom - your argument makes sense, however i think that developing a tiered pricing for viewable on a CPM and the rest on a performance basis would be a great idea. Regardless of CTR and CPC, which are not the primary metrics to be evaluating, the engagement and effectiveness of online ads at driving awareness and traditional brand metrics is the end goal and that is what a correction in measurement and pricing would alleviate.

  2. Dark Knight

    If publishers stop selling out of view impressions, doesnt this problem go away? It then wont be validated, it will just be the norm?

  3. Alejandro Correa

    Hi Tom,

    Great article, and I agree with you on the true "value" of viewable impressions.

    Pricing on viewable only is like a fishmonger only charging you for the filet, and not for the bones or skin. The fish would end up costing exactly the same, and it would increase the complexity involved with buying it.

    As a buyer though, I would be curious to see the degree to which ads are viewable on individual URLs. It would be interesting to analyze performance against this metric.

  4. What are your thoughts in regards to viewable impressions when looking at view thru attribution? Many of these impressions that are unviewable are just cookie bombs, trust me, I've seen this happen.

    Websites that look like NASCAR race cars are not good for the consumer experience.

  5. Alejandro, great analogy! I wish I had thought of that for the article. Ultimately as a buyer, it seems to me you want to know what drives results, so if a top banner drives X lift and a bottom banner drives Y, you should buy based on X and Y, not "viewability".

    Cory, I don't see the connection between changing the definition of an impression and measuring engagement and effectiveness. If you measure cost per unit effectiveness, then intermediate metrics are only about shifting risk between the advertiser and the publisher, and I don't think we need a new one. Good piece in MediaPost, though.

    Dan, I'm all for eliminating fraud, but I don't think we need a new metric for that.

    Dark Knight, you are right, but it will cost a lot, cause a lot of confusion, and ultimately add zero value. So why do it?

  6. Tom, your view on ROI may be valid if indeed CPV prices are being raised comparable to the waste that's being eliminated. However, in my opinion visibility does add a valuable component to understanding the value of digital media. Measuring exposure in terms of 'time in view' rather than waste and visible impressions and relating this to actual brand effects deliver insights that form the basis of next level digital marketing. Visibility alone is not the answer, but adding time of view and reached audience should set up marketeers to really understand digital brand building.

  7. Hi Tom,

    While I agree with you on the fact that "viewable impressions" do not necessarily improve marketing ROI, at least straight away (and some people are using it to feel that they 'get' digital), I think this is a long overdue standard. I think that anything that improves transparency is useful. Think of the inefficiencies it will help eliminate in the long run.

    I also respectfully disagree with Alejandro's analogy. I think an non viewable impression is equivalent to a fishmonger asking you to pay fillet price for the skin and bones.

    I know it is hard and taxing (in the short run) but an absolute necessity.


    • Alejandro Correa

      ...but the price of skin and bone is already factored into the price of the fish. No one prices fish on just the filet because it would be a pain to dress before it was weighed, and smart buyers know how to adjust for weight of bones and skin. And if you think your fishmonger is selling you thick-skinned, heavy-boned fish...then don't buy from that fishmonger.

      I won't overburden my already flimsy fishmonger analogy; to get to the point, I think it would be wrong to use viewable impressions as a way to beat publishers up on price. Standdard Display inventory is for the most part not over-valued, at least not through RTB. If we start paying on viewable, this means that either pubs are going to raise the price of viewable so they end up making the same amount, or pubs are going to make even less.

      I'd like to get metrics on viewable by URL so its easier to weed out the crappy sites with 90 banners on them which we go to great pains not to put on our whitelists anyway. But to add even more complexity to the already convoluted process of buying an impression through an exchange is madness.

      Where viewability metrics might make sense is on video, where there is a lot of optimization being done towards "completion." I would wager that placements with high completion rates either have low viewability rates, don't have a skip button, or are soundless autoplay.

  8. Viewable impressions is a simple concept that most clients intuitively agree with. The market will be willing to pay a premium for VCPMs. I've been talking about this for the past month and it's easy to build consensus. Who cares if there is a small tax for measurement/auditing? There is already a ton of complexity in the way we do business. At the end of the day, viewable is important and will stay as it is the right thing to do for advertisers. Brand metrics are hard to move when only 69% of your paid media is in view.

    The 3MS objectives are critical to moving the industry forward but we have to start with the basics. Placing a value on viewable impressions is a great starting point. Next on the list should be to create standards for measurement that are transparent for publishers, advertisers and agencies. All parties involved should be able to log on, in real time, to see how publishers are performing against campaign averages and industry norms. Progress is stifled when proprietary non transparent measurement black boxes are used and defended as fact.

  9. Tom,

    I am pretty much right in line with what you're saying. In fact, I blogged about it a while back, here:

    However, the biggest problem with out of view impressions that is not being addressed is that 99% of DR campaigns through big agencies still attribute conversions on the last-ad-seen basis and will give 100% of a conversion to someone who ran a cheap CPM ad on the bottom of a page where the impression was never seen.

    I agree with you that Frank at C3 beats this drum way too hard. Attribution is about much more than last ad seen. But, in this specific case, literally billions of dollars are being spent, valued, and judged on a very faulty metric.

  10. Among other reasoned discussed, I support "viewable impressions" because it will help separate the good guys from the bad guys. I agree with you that from a macro view it won't make any difference because the non-viewable impressions are already baked into the price. However, sites with a higher concentration of viewable impressions will be the winners and those with a low concentration of viewable impressions (lots of below the fold inventory) will be the losers.

  11. Finally, some sanity around viewable imps - Tom, I'm in complete agreement this is yet another technical distraction from fixing the real problem, which is proper attribution (to Jay's point) and ROI measurement online. The only good thing I see about viewable imps is they serve as a band-aid on the last touch attribution model, but rather than fix the root issue, this industry looks to another shiny algorithm to cure all their woes.

    Switching to a viewable impression sounds like a great idea in principle, but when you think about the practical realities of moving toward that standard, it introduces tremendous complexity - how do you define what's viewable and what's not - how will you technically execute that - how do you audit and ensure there isn't a way to corrupt the process - we'll all be so busy patching this technology for the next two years that we'll keep ignoring the real issue we need to solve for - proving the value of digital media.

    Why are we yet again agreeing to be held to such a higher standard than traditional media? We're in an arms race with ourselves for the same piece of budget - this isn't going to move share from traditional to digital, so we all should save our energy.

  12. Justin Gospodarek

    I have to agree with Joe. It's the low quality BTF placements that have cluttered up the landscape and have greatly contributed to the users' filtering of ads. If pubs cleaned up their pages and focused on a few high vis placements, we could reverse that trend. The lift on performance could easily outweigh having that space available. Not to mention, the user experience would become much better for most pubs.

  13. I am a huge fan of the viewable impression. As someone who is on the demand side (agency), I have been pushing for this for a while now and have been a public commentator for comScore's recent vCE announcement.

    I like knowing what I buy on behalf of my clients will be seen. If they are not seen, I do not want to pay for them. Better yet, I want to make sure what I am buying for my clients are seen by the right audience. If not, then receive makegoods or similar. For far too long, the publisher side has manipulated this to work in their favor - which is why a "Yield Manager" exists on the publisher side.

    Now, this brings a bit of balance to the demand side and allows us to buy in a better environment and should see a rise to performance (relative or not relative to pricing).

    The publisher side, of which you represent (btw - a fan of your organization) is surely impacted. And for many publishers, impacted negatively. This is not an easy framework to deploy becauses it could have balance sheet implications. I believe this will clean up a bit of the web and make it harder for cookie bombing and the like.

    This is a big step forward for the marketing technology ecosystem which will eventually translare across media channels.

  14. Tom, a thoughtful contribution to the discussion, thank you. I subscribe to your point on where the industry should place focus.

    Viewable impressions have become a hot topic, however the majority of my conversations with buyers/sellers indicate that the biggest question on the table isn't whether an ad is in view or not, but rather, "how do we prove that our digital strategies align with/create value/drive sales for the client?".

    To your final paragraph, maintaining a focus to determine and align ROI for cross-channel investments (TV, mobile, video, social et al) as it relates to sales (actual ROI) likely benefits market growth (and addresses pain points across the ecosystem) more than the creation of a "VCTR".

  15. First up, this is a fantastic exchange of thoughts! Although, I don't think the industry needs to "move" towards viewable impressions, I do think its a very important metric to report and optimize on. Anything that adds transparency and drives efficiency (separate the good from the bad) is good for the industry. Tom, although I agree to some extent that perhaps this is not the most important piece in the entire display puzzle, I have to disagree with your argument. Obviously, the price of good apples will increase when we separate out the good apples from the bad apples, but this will create a great incentive for those supplying bad apples to change. Also, I am sure marketers will feel much more confident when buying a basket full of good apples at a higher price than a mixed basket at a lower price. Isn't this the premise of RTB as well to an extent when we talk about bidding by fold, bidding by publisher, bidding by size, etc?

  16. First, thanks everyone for the terrific and constructive comments! I'm delighted this article helped spark some good conversation.

    In response to several people, I agree that "viewability" is a useful and interesting metric as part of an analysis of what is working and what is not, along with geo, placement, and other characteristics. My main point is I don't think it adds enough value to justify changing the standard currency of digital advertising we have used for more than a decade.

    I love the focus on figuring out what actually drives brand lift - if we can crack that one, we can really grow the pie for everyone.

  17. Wow. It's kind of shocking to write that a measurement of whether consumers actualy have the opportnity view an ad or not, is a bad idea! Can you imagine having that discusion in any other medium? I'm not talking about OTS (Opportunity To See)measurements. Non-viewable impressions equate to NOTS (no opportunity to See). How many NOTS equal an impactful ad campaign? How many NOTS can any publisher sell?

  18. I completely disagree with this article. The number of out-of-view impressions that are being bought is obscenely high in many circumstances. Being able to measure viewable impressions through to attributed sales will help us understand the real impact of display advertising, not just as a direct response vehicle, but also how it performs higher up the funnel. It will also stop many publishers from being lazy with how and where they serve ads. Clients want transparency, they don't want to buy millions of cookies without understanding the true incremental impact of their media spend. I feel the viewable metric will help to bring much needed scarcity to this overcrowded landscape. Right now a 'million impressions' is a meaningless stat.

  19. Blake

    I understand the author's point, but could it be that the CTR and CPC/CPM are not the most valuable metrics to be looking at when discussing the viewable impressions debate?

    The digital era has allowed the opportunity for measurement in ways that have never been possible before (that should go without mentioning in a forum like this one). If i pay for 1,000 impressions and only 500 of them are seen, it is impossible to get anything more than a 50% conversion rate at the very maximum (depending on how you report on conversion rate - click to conversion/ impressions to conversions). Meaning that my cost per conversion - which is what ultimately should matter the most - can also only be half as efficient as it could potentially be if all other factors are perfect (which they wont).

    Granted these are intentionally simplistic numbers for the sake of making a point, but there has to be a sophisticated way of measuring media and analyzing the data in place in order to see the true value for each buy on a network/site/placement level...etc.

    It only makes sense to ensure that the most basic part of this equation isn't flawed from the start - if the impressions are not viewable there can never be true measurement or attribution model in place. Only when we have full transparency into what we are buying can we even begin to measure the cost to waste ratio to see effectiveness.

    Additionally, what is true for one advertiser will not be true for all, so I encourage any advertiser agency to put it to the test. Measure what is important and then if there is room in the budget try a test to determine what is viewable. If it turns out you are in the group that is seeing high waste, adjust your buy and optimize toward conversions rate and cost per conversion.

    This is the only way that any of this matters. Otherwise, as some others have said, we are simply talking about paying more for a basket of only good apples, which in my humble opinion, completely misses the point.


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