Importance of the order of ads within the HTML code

It makes no difference.

Thank you frankleeceo!

Not so fast. I think it *does* make a difference.

Think about it for a second. AdSense works by going and finding a match for your page. It's an auction, and the best-paying advertiser - "the winner" - gets the slot.

If you have two slots in the page, the auction runs twice. And the best-paying advertiser will get the top slot, but mightn't get the second slot, depending on the rules AdSense is running. So you get the second-best advertiser in the second slot.

And if you have three slots in the page, the auction runs three times. Will the advertiser in slot #3 be the third-best winner? In many cases, yes - since Google clearly doesn't put the same ad in all three slots.

So, if you think about it, the number of slots and when they're called *must* have an effect.

So... what happens if you have a page looking like

editorial   sidebar
editorial   MPU
editorial   MPU
editorial   MPU
editorial   MPU
banner    sidebar
editorial   sidebar
---PAGEFOLD---
editorial   sidebar
editorial   sidebar
banner    sidebar

... but the code actually looks like...

DIV for main page
editorial
banner
editorial
banner
DIV for sidebar
MPU

... the MPU is third in the code, even though it displays before the second baner.

The question is whether the MPU gets the third-best winner (i.e. the second banner auction is run before the MPU), or whether the MPU gets the second-best winner (i.e. the banner auction itself isn't run if the banner is wholly invisible in the viewing port).

As far as I can tell, the MPU code is run third (but it benefits from having a better ActiveView score): unless you're running AMP pages, which have lazy-loading implemented.

Google clearly doesn't put the same ad in all three slots

I see it all the time on my own site as well as on others. Agreed it is not supposed to happen, but it does... alot.

Fair enough. But it doesn't always do that; and it would be a strange algorithm if it does.

And, more to the point, I now discover that Google said (in 2006) that the order matters:

Currently, the first ad unit on a page always shows the top ads that win the ad auction. Also, if there aren't enough ads in our ad inventory to fill all of the ad units on a page, the first ad unit on the page will display ads first. This is why I recommend using custom channels to determine which of your ad units has the highest CTR, and then placing that ad unit first in the HTML code.

For the purposes of this post, the first ad unit on the page is defined as the first instance of the ad code within the HTML of the page. Keep in mind that the first ad unit in the source code is not always the first ad unit that your users will see when the page finishes loading in their browser. For example, if you use DIV tags, our system may recognize an ad unit which users see at the bottom of the page as the first ad unit.

Source: [adsense.googleblog.com...]

Ah! Thank you very much for your enlightenment!

It is all about position on the page, not where the ad code appears in the overall code. An above the fold ad will always perform better than a below the fold ad.

See example 2 here:
[support.google.com...]

Hi, Nick, I don't think I disagree that position is important, and that an above-the-fold ad will perform better than a below-the-fold ad. But I think you're wrong to discount the position (and order of) the ad code.

I bet that in the above example I give, where the MPU appears above the fold but is third in the code, if you changed the order of the HTML code to make that MPU be called either first or second, it would achieve significantly better revenue. Google have confirmed this in the past, too, as I've linked to.

Unless you have any data showing the effect of code position is immaterial, you probably shouldn't be discounting it based on a hunch.

@James007 This is not based on a hunch, Adsense is pushing sites to use asynchronous code. Any new ad code you generate is set async by default. So if your site was designed in 2006 and your still using this old code then maybe. But I you are using async code I doubt the position of the ad code within the html code has any bearing. If you are not using async ad code I would strongly suggest switching, otherwise there is good chance that your ads are slowing your page speed. Since page speed is a ranking factor the benefit from it far out weighs any marginal benefit obtained by optimizing the placement or ad code within your html.

Hi, Nick. You're right to point to the AdSense code having changed since 2006. However, the asynchronous code is a bit of a red herring - you only call the adsbygoogle.js code (which is asynchronous) once. (FAQ #3 at [support.google.com...] ) - it then walks the DOM and discovers how many ads are in the page, performs an auction on each of them, and displays the ads. So what we need is a bit more data to be able to answer the question "does it matter about the order of the ads in my HTML code".

The adsbygoogle.js asynchronous script uses show_ads_impl.js to actually bring those ads up, and there's one call per ad slot. With Chrome's developer tools, you can see the timing of when it calls the ads with this script. And it's interesting to do so. When you have a page looking like the above example - a banner (1) in the page body, another (2) in the page body footer, and a third (3) in the sidebar on the right - banner (1) and (3) appearing above the fold - then the creative for number 3 loads last. I've now run this test a number times on my production website. The creative for (2) loads before (3), even though it's below the fold.

So, changing the order of the ads in the code will increase revenue, since ad (3) would then load faster than (2), and your visitors have more chance of clicking it.

What we don't know is whether the auction still works the way it worked in 2006 - that the first ad call gets the top-performing ad. What I can tell you based on six months of data is that adslot (1) performs significantly better in raw revenue terms than adslot (3). That could be related to the fact that it's in the page copy, rather than shunted off to the side, so gets more clicks. Or it could be related to the fact that adslot (3) is third in my code, and gets the third-best auction result.

So: I have at least two data points showing that order of code does appear to matter. I also have a ten-year-old blog post from Google telling me that, then, order of code does appear to matter. My view, based on data, is that the OP should engineer his site to load the ads in order of visibility: so that the ones at the top of the page are also loaded first in the code. And, frankly, so should I!

Earlier, I said:

As far as I can tell, the MPU code is run third (but it benefits from having a better ActiveView score): unless you're running AMP pages, which have lazy-loading implemented.

I'm not sure I'm right. In my tests, it appears that AMP code still displays ad (3) last in most cases - but I've had some examples where ad (2) - the one below the fold - loads last. That's the exception, rather than the rule. I'm a bit disappointed by that, to be honest. So, at least visually, the order of the code even matters for AMP pages.

james007, did you notice ads loading faster on your AMP page? At the AMP site, they claim that A4A loads faster than "traditional" ads.