It’s About Time: Measuring the Impact of Advertising

Picture1Advertisers need cross-platform and cross-media metrics. Reach and frequency have long been at the heart of media trading and media evaluation. Yet the link between these metrics and potential exposure and cut through varies between and across media. So what other metrics should be considered?

Measurement of reach differs between media: in most countries, somebody reached by a television ad is defined as being in a room in front of the screen at the moment a commercial airs. A press ad, in contrast, simply has to be placed anywhere in a publication which somebody has read any part of to be counted as ‘reach.’ A digital display ad needs to have initiated a load onto a user’s device to be counted in the reach calculation.

Reach is clearly not the same as impact. Quite apart from the differences between media, somebody reading an entire magazine they subscribe to every month is given the same value as somebody glancing through it in a waiting room. Somebody browsing past a web page for a few seconds is treated as equivalent to somebody staying on the page for ten minutes to read the content.

How can we move beyond reach? Time can be considered as one quantifiable measure of people’s attention. It is already incorporated directly into television audience measurement and, to a lesser extent, into radio measurement. A handful of newspaper and magazine publishers are trialling time-based metrics to market their online advertising inventory.

Softer engagement measures, such as what people say they feel about particular programmes or magazines, tend to be more subjective, changeable over time and place and harder to compare between different media.

Eye-tracking, which offers a measure of eye ‘fixations’ for screen-based media could be considered as an even closer measure of attention than time spent. It has become more scalable in recent years, but it is still too soon to apply such a measure across the board.

But time is not a panacea, any more than audience reach is. It too has flaws and limitations as a measure. One minute spent ‘watching’ a TV commercial is unlikely to have the same impact as one minute browsing a website where a banner ad is sitting on the page or one minute spent with a newspaper where an ad is buried in the middle.

Advertisers certainly don’t value time in the same way between media. Data comparing the amount of money they spend with the various media and the amount of time people spend exposed to advertising are not correlated. But despite this, they give us clues as to likely future trends in advertising expenditure.


Reach is a necessary, but far from sufficient measure of media impact. Definitions of media reach vary between and amongst media types. All measure ‘opportunities’ to see an advertising message rather than actual exposure.

But opportunities to see advertising vary in their likely closeness to actual exposure.

Time is a metric that can, in principle, be used across all media. It is already built into the measurement of television and radio audiences and is available from many digital audience measurement systems. Time spent reading is also asked about in a number of readership studies.

Time spent is a ‘hard’ metric, in contrast to softer measures such as people’s subjective opinions on their ‘connection’ or relationship to the media they use. These can vary over time and between different contexts.

But if time spent can be a useful surrogate for attention, it has limitations. Methods of calculating time spent vary between media. The number of ads in view in any given minute and the context in which they can be seen also differ by medium. As a result, the value of every minute is different for an advertiser. That said, every ad still has an opportunity to break through in whichever medium it appears.

A simplistic comparison of the share of time spent and the share of advertising expenditure by medium – often cited in media reports – is a flawed one, even when the data suggest the future trajectory of media spending accurately.

What is clear is that advertisers need to consider a range of measures (reach, frequency, time spent, attentiveness) when deciding where to invest their marketing budgets.


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