Metrics for Measuring Ads: A Guide to Success
5 min read

Metrics for Measuring Ads: A Guide to Success

Measuring the success of your ad campaigns can at first seem almost bewildering. Say you’ve just launched your latest display advertising campaign, or maybe you’ve sent out your latest email newsletter, and you want to see how successful it has been. You wait a while, then hit refresh on your analytics page. You’re hit with number after number, graphs, and pie charts for as far as you can scroll, but which is the most important? Which metric matters most?

What if your impressions have risen, but the click-through rate (CTR) has dropped?

What if people have spent less time looking at your ad, but your conversion has somehow improved?

What do you do if your email open rate is sky high, but your audience isn’t doing anything after opening?

There’s a reason behind everything, but it can be difficult to dig through the data and discover what’s going on. Some metrics are more reliable and useful than others, though, and here’s a quick rundown of the pros and cons of the most common ways to measure the success of your campaigns.


The total number of impressions equates to the total number of times your ad has been served. This doesn’t show the amount of individuals that have seen your ad, though, as it may be shown to the same user more than once.

Impressions as a metric give you a fairly good idea of how your ad is doing in general terms, but as a statistic on its own, it’s not so useful. It doesn’t give you info about overall reach, or conversion. It is, generally speaking, the way you pay for your ad campaigns, which is why it tends to be such a common metric. You’ll usually pay a set fee per impression.

One big drawback of making any sort of judgments based on impressions is that you don’t know if the user is actually seeing your ad at all. It could be that it’s served, but they just scroll right past without paying any attention. Of course, whether this is the case is partly down to the ad itself, and whether it’s designed well enough and effectively targeted.

Overall, while impressions are useful and will likely dictate how much you pay for an ad campaign, you need much more supporting info from other metrics to draw any reliable conclusions as to whether or not your ads have had any real impact.

Click Through Rate

Click through rate, or CTR, is exactly as it sounds. It measures the number of users which actually click on your online display ad, whether that takes the form of a native advertisement or a banner.

It should be the case that this is a really reliable metric, as it represents a tangible action being taken by the user as a result of seeing your ad. You’d think that the higher the CTR, the higher the conversion rate.

Unfortunately, nothing is ever that easy in the complicated world of display advertising.

Comscore found, in fact, that there’s almost no link between CTR and conversion. Surprising, but the wide-ranging study covered over 250 million impressions over 9 months, spread across 18 advertisers, so the results are reliable. Interestingly, click throughs had a lower correlation with overall conversion than either viewable or gross impressions.

There are a number of potential reasons for this, but the big one is that hardly anyone actually clicks on display ads at all. Whether native or banner, the proportion of those who click through is tiny compared to the number of people who actually see the ad.

This doesn’t mean the ads aren’t effective, though. A user may see your banner, and be drawn in by it, but then make their own way to your website later on. This is why you need to monitor view-throughs too, which take into account the users which have seen your ad who then visit your website within a certain time frame of your choosing.

When you look at this in conjunction with the CTR, you should get a much clearer picture of how your ad is performing, and what effect it’s having on your conversion.

Time-Based Ads

Strictly speaking, this isn’t yet a metric of measurement but is a relatively new way for publishers to charge for ad inventory. So, rather than charge per impression, they charge for a certain block of time. This can be anything from 10 to 30 seconds, and the publishers guarantee 100% visibility for that amount of time.

While this isn’t strictly a metric you can measure on directly, as an advertiser it’s something worth looking into when buying inventory. If you do this, and compare results (so overall conversions, view-throughs etc) to that of an impression based inventory buy, you could potentially see a big difference.

Only a few websites are working this way at the moment, but it could be the best way to buy inventory, and measure success, in the future. The reasoning behind this is that it’s such a reliable way of measuring engagement. After all, the longer an ad is in front of a user, the more likely they are to at least notice it, as opposed to if it’s just an impression where the user just scrolls straight past.

From there, you can analyse how this method compares to the impression based models, based on budget, and overall ROI. Just ensure you’re testing the same ads and using the same view-through parameters, so you’re getting like-for-like results.


This is a similar sort of number to the impressions, but instead of counting the number of times the ad is served, it counts the number of different users which have seen the ad. Or rather, potentially seen. The figure still doesn’t take into account whether the user actually looked at the ad, but it’s still a useful metric.

After all, this is the figure which gives you a rough idea of your overall reach. Of course, the ad isn’t always seen, or even fully in view if it’s placed ‘under the fold’, but as a figure it still allows you to measure the reach of one campaign against another.

Conversions/Return on Investment (ROI)

For most advertisers, this is going to be the most important metric of all. After all, if you’re investing money in advertising, the sole purpose is to make more than you invest. Even with this relatively straightforward metric for measuring success, there are still a few variables you need to be mindful of.

You may just be measuring direct conversions from the display ad itself. This essentially means the number of people who click on the ad and convert into customers/subscribers/do whatever you’re asking them to do.

Fine so far? Good.

But what about all the people who see your ad, pay attention, but don’t actually click? Instead, they make a mental note, and come back to your site later via a quick search, and then convert into customers.

After all, this is extremely common, and is a direct result of your ad campaign, but these users might not be counting towards your ROI. This is risky, as it will make your campaigns look as though they are performing worse than they actually are.

Once again, this is where you need to take view-through into account. These have been criticised in some quarters, but like any metric, it’s really useful if you’re using it the right way. Set a defined window, and this will tell you how many users have come to your site through other avenues, having seen your ad earlier.

If you do this, you should be getting quite a full picture of your bottom line conversion, which most marketers will find incredibly useful. Of course, it’s still not telling the full story, and doesn’t take into account brand awareness and reputation, but it’s an incredibly important stat, as it attaches hard figures and shows you if your investment is paying off.


In the world of online display advertising, there are so many metrics and even more ways for marketers to interpret them. These are a few of the main ones, but there are many, many more.

The key is not to pick one and run with it, but to use a combination and discover what works best for you. Ultimately, overall conversions are the key to a successful campaign, so if these increase from advert to advert, then you know you’re improving.

However, potentially the most interesting and reliable way of actually paying for your ad to be shown to your audience is through the time-based method. This guarantees that you will have your ad in front of your audience for a set period of time, so the user is much more likely to see it properly, if not engage with it. This, in turn, raises brand awareness, which means they’re more likely to revisit your website later on.

This is also why you should look at view-through statistics too, which brings us around nicely to the fact that no single metric is best.

Instead, a combination of a few, which are then compared with old campaigns or used side by side in A/B testing, will give you the most meaningful, accurate, and useful results. Then you will know if your overall campaign has been a success.

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