Read our new manifesto

Explore our new sections and topics

Moving beyond hover rate as a metric of success

For many, the promise of digital advertising is the wealth of data and information that comes with every ad impression bought. However, all this data becomes virtually useless when marketers employ the wrong success metrics for their campaigns, as Integral Ad Science UK managing director Niall Hogan explains.

What use is it to know your click-through rate if more than half of clicks seen are in fact from fraudulent (bot) activity? And how much do you really gain by optimising for lower CPMs if your impressions are all showing up in non-viewable placements on a web page?

Unless marketers are able to judge effectiveness of their online spend using metrics proven to positively impact their business results, there’s no reason for them to trust digital media any more than they do other media, such as radio or print.

One main area where Integral Ad Science is seeing marketers, and some ad tech providers, making a huge mistake is placing value in metrics based on how people move their mouse cursors while browsing a web page. Although conventional wisdom suggests that someone is likely to be looking at an ad if their mouse is hovering over it, recent research suggests this is in fact not the case.

UK consumers today have vastly different browsing habits to even a few years ago. A study we conducted back in September 2015 examined billions of impressions and found that marketers who optimise their campaigns using mouse-based metrics actually increased the likelihood of attracting fraudulent traffic, as a bot would learn to mimic human ‘mouse movement’ behaviour.

The study found mouse cursor hover rates 27 per cent higher on impressions that were blocked (blocked impressions were those seen to pose a high risk to brand-safety or seen to have fraudulent activity). Simply put, these kinds of statistics are woefully inadequate for determining the success of an online ad campaign, and they need to be abandoned.

User browsing habits have changed

Much of the trust our industry places in hover rates and heat maps dates back to a 2001 study conducted at Carnegie Mellon University, which suggested a “strong relationship” between a person’s cursor location and where they were looking on the page. As a result, the authors concluded, companies could use mouse-tracking as an inexpensive alternative to eye-tracking systems.

Nearly 15 years later, the paper is now very much outdated, particularly when it comes to how people browse the web. At the time of its publication, virtually everyone was accessing the internet from a bulky desktop computer and mobiles had little functionality beyond making calls and the occasional game of Snake. Not only do today’s consumers have vastly different browsing habits but we are now also able to collect a great deal more information on how they use the internet.

It’s no surprise that user experience experts from both Google and Microsoft have since produced research directly contradicting the findings of the 2001 study. In a 2010 presentation in Belgium, Google’s Anne Aula explained that 42 per cent of the search users the company studied had no active mouse movement as they attempted to complete a task on a web page.

Further, of the remaining 58 per cent of participants who did move their cursors during the study, the eye movements of just 32 per cent matched their horizontal mouse swipes, while only 10 per cent exhibited a relationship between their eye gaze and their vertical mouse movements.

Additionally, a team of scientists from Microsoft and the University of Washington concluded in a paper published in 2012, mouse movement is ultimately useless in terms of predicting whether a user has seen an ad.

The paper cites that: “Cursor movements, scrolling, and other client-side interactions are easy to collect at scale, which many web analytics services offer to do. But claiming that the cursor approximates the gaze is misguided – as we have shown, this is often not the case depending on time and behaviour.”

Not only is mouse movement ultimately useless in terms of predicting whether a user has seen an ad, optimising campaigns for hover rate is actively damaging to marketers’ efforts to reach their target audience. Fraudsters have in recent years found ways to game the system by programming bots to wiggle a virtual mouse over the area where an ad is supposed to appear, thus fooling measurement vendors into thinking a real person saw the impression in question.

The September 2015 research project from the Integral Ad Science data science team actually found a statistically significant correlation between hover rate and ad fraud – hover rates were 48 per cent higher when served to bots rather than humans.

While many marketers see a relatively high hover rate as a sign that they’re running a campaign with great viewability, the truth is they are more likely being swindled by fraudulent actors.

This article was first published in the 1 June issue of The Drum.