But ultimately, is striving for the highest possible rate necessary – or can we simply live without it as a metric?

The IAB and MRC define viewability within display advertising as “at least 50% of an ad must be in view for a minimum of one second for display ads and two seconds for video ads.”

While this definition has stood firm for several years, can we confidently say that our target audience has seen the ad, let alone registered any content within that ad, within that timeframe? Or that it would generate an action or uplift in brand affinity? Hardly.

You could describe the definition as being binary: either an impression is viewable, or it isn’t; a fraction either side of second can make a massive difference to its classification as ‘viewable’. But clearly that additional millisecond has no effect on the end consumer.

On the flip side, once deemed ‘viewable’, all impressions are treated alike, which fails to make a distinction between ads viewed for one second or ten.

Three ways to boost brand safety in the programmatic age

As the industry continues to mature, its vital verification tools keep up with advances in formats and ad types, particularly if viewability is so important. The current rise in native advertising is only adding to this challenge.

Unlike traditional banner ads, native ads can’t be treated in the same way making it impossible to measure and report viewability, even though we know people are more likely to click a native ad over a traditional banner.

What does this mean in practice for agencies and clients?

Most clients instinctively believe higher viewability rates are optimal; however, this is not necessarily the case.

Restricting campaigns to a predefined, pre-bid viewability could result in reduced inventory, higher costs and missing out on potential audiences. Naturally there might be a fear that performance could suffer if ads are shown in less ‘viewable’ spots, but this is something you can monitor.

Crucially, lowering your viewability does not mean that you’re lowering brand safety standards. Your white and blacklists, along with negative keyword lists and even ad position should take care of this.

Assuming those safeguards are in place, you’re ready to stop using viewability as a primary metric.

While this isn’t going to change the fact there are some key flaws with the current viewability definition, rather than focusing on an overall viewable rate, viewability should be seen, and optimised, on a cost per viewable impression basis.

Why cost per viewable impression works

With higher viewability often comes increased competition and eventually inflated costs for ‘viewable’ inventory. However, this doesn’t always mean premium inventory, and as a brand you’ll be reducing your overall campaign reach.

Viewable % Cost CPM Impressions Viewable CPVI
75% £1,000 £2.20 454,545 340,909 £2.93
50% £1,000 £1.40 714,286 357,143 £2.80
25% £1,000 £0.75 1,333,333 333,333 £3.00

As in the example outlined above, by dropping this rate, inventory availability increases, and CPM rates fall resulting in more impressions delivered and greater reach for the same budget.

We are assuming here that exactly X% of all impressions are viewable. Often this isn’t the case, and as a percentage, viewable impressions are higher than predefined. This only looks to demonstrate how changes in viewability can have a real impact on both reach and cost per viewable impression.

What does this mean in terms of performance and efficiency?

Finding the optimum point is key to getting the most value out of your budget, achieving the greatest possible reach at the lowest cost per viewable impression.

CPVI might not be available in any default report from your DSP but is a metric worth investing time in, particularly if viewability forms a big part of reporting campaign effectiveness. Don’t just fall into the trap of setting high viewability rates.

Where does this leave us as an industry? This simple change in programmatic practice can have a positive impact on performance and efficiency, getting more of your ads seen by your target audience.

As an industry we should be focusing on ad engagement and dwell time and moving away from the current black and white approach for viewability where a single millisecond makes all the difference. What really matters for performance is the time a user is exposed to your brand, not necessarily how many ‘viewable’ ads we can get in front of them.

The future for advertisers is to understand the optimum exposure needed to drive the best results. Only then can we truly identify ad spend wastage.

The CMO’s Guide to Programmatic