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Impression Share Mania: The Use and Abuse of AdWords Most Misleading Metric

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Impression Share Mania: The Use and Abuse of AdWords Most Misleading Metric

Hi everyone, welcome to the Paid Search Magic Podcast.

This week Amy and I are talking about a single metric: Impression Share. We bumped it up to the front of the queue because of how misunderstood and misused a metric it is. All-too-often it’s considered to be a Key Performance Indicator, and as a KPI it’s terrible. It’s the kind of metric that seems straightforward, but has a closet full of exceptions and qualifications which make it dangerous to make decisions by.

So whether you’re a paid search professional or a business owner, you need to understand the use and abuse of Search & Shopping Impression Share so that the decisions you make improves business performance, not an arbitrary metric infamous for it’s imprecision and misuse.

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James: Hi, Amy – how you doing?

Amy: Pretty good, how’re you?

James: Good, thanks for joining me today.

Amy: Of course.

James: So, today, we’re going to be talking about the impression share. And this is an interesting metric. It’s something to kind of gauge your competitiveness, but it has a long insulate past. So, let’s give you a quick definition.
The search impression share is essentially the number of the times that your ad shows up divided by the times it was eligible to show up. And so that means that you’re going to get a percentage, right? From zero to 100 percent, theoretically.

Amy: Okay.

James: The key part of that is, like, the number of times your ad was eligible, so those aren’t the same numbers, right? Whenever you enter your ad into an auction, you’re going to have a bid, and you’re gonna have a quality that goes into that, and it’s gonna determine whether or not you’re showing up.
So, if your ad is competitive, then that’s gonna count as like an eligible impression, essentially, even if you didn’t show. If your bid is like terrible, if you’d have to multiply it by a thousand percent just to be competitive with the other people that are in the auction, then it wouldn’t count.
So it’s kind of a fuzzy metric.

Amy: Yeah, it gets a little bit weird if it’s like, sorry your ad didn’t show because your bid was too low, versus your bid was so low that not only did it not show, but it wouldn’t have ever been eligible, so we’re gonna remove that from the calculation.
Like, that’s weird. We have to admit that’s weird.

James: Yeah, it is, and it’s always been this way. It’s an incredibly misunderstood metric, and I don’t think that has changed a whole lot anytime recently.

Amy: Right.

James: But what’s the reason to why we’re talking about it today? So, we can say right there, already we know it’s a fuzzy metric, that it can be a little bit misleading or misunderstood. Why are we talking about it today?

Amy: Yeah, so it’s fuzzy, it’s an estimate, and to your point, like, impression share, had the way it’s calculated has not changed. But what is, I would say is changing, and that is increasing over time, is a client’s desire to use impression share as a KPI.
Like, it was a bad idea years ago, it’s a bad idea today, but there seems to be a growing push to try to use you know, a key performance indicator like, this is how we’re measuring the success on the account based on impression share. And, that’s a bad idea for many reasons, like there’s not a good reason to do that.
But it’s like, kind of a fan favorite among marketing managers, or CXO, like it’s really desirable because it’s a very emotional, like, kind of an emotionally charged metric. And by that I mean, it is an estimate, right? But you don’t have to understand all the data, like, you know, pan search is very much in the weeds, and impression share is a little bit removed from the weeds, and so it’s very easy to react to, because you can just look and say, hey, if I have a hundred percent that’s good, the closer it gets to zero is bad, I don’t need to understand all the nuances, I just can look at this and say, are we winning or not?
And so, especially for people who are a bit more competitive, who does have this goal of like, leading the pack and dominating, and they don’t wanna hear the whole ‘it depends’ [inaudible 00:03:16] that can sometimes accompany other metrics. This just tells them the story, it’s a quick measurement that says, hey, we’re doing great, or we’re not doing great.
And it feels very fixable. So, like, and I think we’ll go into this a little bit more of how you would affect that impression share, but it’s like, okay, well, if the impression share is down, it’s because either we need more budget, or we need to do better. Our [inaudible 00:03:41] needs to be better. And either of those are fixable.
We can increase the budget, we could, in theory, make our ads more competitive.

James: Increase the bids.

Amy: Sure, yeah, increase the bids or the budget, something to do with money, right? Or something to do with quality.

James: Which isn’t the easiest lever to pull, right? ‘Cause, yeah, you can improve the quality, that’s a whole different level of affecting things, whereas a bid is just, yeah, I’m gonna increase the bid by 20 percent.

Amy: Right, and so it can kind of be a little bit of ammunition to go back and say, hey, we need more money, because, look, we don’t have all the dominants we wanna have. It’s like, if you have 100 percent impression share, that’s indicating you’ve got a really good reach, and you’ve got a really good share of voice, you know, air quotes, but share of voice.
And then, it suggests that you’re not missing any sales, or any potential for sales. So, especially marketing managers that are very driven by the fear of missing out, and we know that those people exist, they wanna make sure that they’re not losing anything.
So, it’s less about being efficient, but more about the fear of loss. This really helps you to counteract, this potential fear of loss. ‘Cause if we have 100 percent impression share, that suggests, rightly or incorrectly, that we haven’t lost anything, we aren’t losing anything.

James: Which is absolutely wrong. I mean, we should just say that straight out. If you had 100 percent impression share on some random campaign, it does not mean that you’re not missing out on sales.

Amy: No, it absolutely doesn’t. It’s like we kicked this off with, it’s not the right metric, but it can appeal. Like, the less you understand about impression share, the more likely you are to sink your teeth into the idea of it. Yeah, this is good, this is our KPI.
And it’s not appropriate, and I certainly don’t mean to be coming across, you know, probably as antagonistic as I sound here, but I think it’s important to, right out of the gate, to start off with, hey, we’re not talking about how to optimize for impression share, we’re talking about how we can actually use it effectively and what to avoid.
What we wanna avoid is those emotion driven metrics that aren’t actually telling the story that we wish they were, and doing that at all costs, where we actually kind of sabotage the campaign because we just wanted what looks like the easy way out but actually isn’t really helping anything.

James: Right, and one of the reasons why we’re talking about this is, it’s not an uncommonly, misused metric.

Amy: Right.

James: We experience this all the time. We experience it with clients, even other markers, I mean, it’s just something that comes up a lot because it is misunderstood. And, like with most data, wrong data or misunderstood data is worse than no data at all, because it leads you to make bad decisions.

Amy: That’s right, and so optimizing for 100 percent of impression share can hurt your account in several ways, and I think that you’re gonna get into the tactical of that, but something to understand from a very high level, is that impression share, there’s no account level impression share.
This is really important, because impression share is going to ignore the broader coverage context. So, if my particular campaign that I’m looking at has a low impression share, but the key words that are contained in the campaign are actually covered somewhere else.
So, for instance, I have terms that I have shopping campaigns running for, and I also have search ad campaigns running for, and there’s coverage in shopping campaigns, so in between that and my organic listing, I’ve actually got a really good coverage on the search results page. I’m not gonna see that if I’m just [inaudible 00:07:04] a particular campaign’s impression share.
So, if I’m focused on that for particular campaign, it can really tell an incomplete story without giving suggestions that hey, we’re not looking at all the data here.

James: Yeah, and let’s talk about, let’s dig into a little bit more, and look at some of the weaknesses, right? So if you go back to the definition. You’ve got all of the impressions that occur, divided by the number of impressions that you’re eligible for.
We’ve already established that what you’re eligible for is a little bit fuzzy. But now, you also have to consider some other factors, and honestly, when I was kind of doing some research for this, I see almost nobody bring this up, and without this understanding of where it’s weak, than it’s being misused.
So, the first thing is match types. You can have a set of keywords, you may very well have some phrase match or some broad match in there, even exact match with its fuzzier interpretation of what counts as quote unquote, ‘exact’, by Google.
You can be pulling in a bunch of different search terms for every keyword, right? So, if you have a broad term, that might be pulling in any number of different search terms. Probably search terms that you’re not counting on.
Anybody who has trolled through a search term report is going to see a bunch of terms that they didn’t want to show up for, it’s not relevant to their product. And, you know, usually the next move is to negative match those out.
But the problem is, is that those still count for what you’re showing up for in your impression share. So, when you have this broad term, it really opens up the number of auctions that you could be potentially eligible for, and even right there, it essentially muddies the metric beyond usefulness.
So, there’s a few ways around it, but let’s get to some other things. So, recently, I knew somebody who wanted to look at impression share year over year by campaign. If a campaign had not changed at all, maybe that would be a somewhat of an indicator.
But the fact is, is that, keywords get turned off, keywords get bid down. Things change all the time. And, this is how it can be so easily manipulated. Now, if you have a campaign full of keywords, each one of those keywords is going to be, you know, more or less competitive, right?
And that’s gonna impact your impression share. If your client came to you and said, hey why do we only have 60 percent impression share, you guys aren’t doing your job, I want to see this up by 20 points by next month.
Well, you could make changes to get it up by 20 points the next day. And the way that you would do that is you would go through, you would look at the keywords that had low impression, you would look at the ones that were broader, and then you just start shutting that down.
Not bidding it down, shutting it down. Which is not a great tactical decision, if you’re looking at proper metrics like ROI, or Roaz. All you’re doing at that point is you’re just shutting down keywords that are dragging down your overall search impression share.

Amy: Right.

James: So, I mean, it’s a really easy way to gain the system, but it’s leading you to a non tactical decision. In this sort of a case, the decision becomes more about just pleasing your client and making them feel like they’re being the competitive, than actually being competitive.

Amy: Right, I had written an article a couple years ago, talking about, just the weirdness of using impression share as a primary goal, and I had found an image to support this of a movie theater with just one person, and it’s like, hey you’ve got 100 percent impression share.
Like, that doesn’t mean what you think it means. If you’re reaching an audience of one, and you’re speaking to them, you have their attention, that’s great but you would much rather be speaking to a full theater of prospects than just one person, and the closer we get to impression share, the more potential prospects we weeded out in the process.

James: Right. So, I’m sorry, there’s so much that we can talk about on this. But, they’ve further complicated it with the addition of shopping, right?
So, just a Segway into that. So, first you had just a regular search impression share, now we have shopping search impression share, and that’s actually treated differently. To some extent, necessarily so.
First of all, when you run a shopping campaign, it’s just fundamentally different from search. You’re not bidding on specific keywords. You have products, and then Google is doing their magic in the background to decide what they want to match you against.
Now, you can go in there, you can look at your search queries, you can negative match it out, but just by the nature of what shopping is, you’re opened up to a bunch of products that you may not want to be showing up for at all. So, you gotta keep that in mind when you’re looking at impression share.
Further, when you’re running shopping ads, you could show up with four different shopping ads. Like, if somebody’s search triggered those ads, you’ll show up more than once. The way that Google calculates that, and actually just found this out recently is that, it’s only like the top most shopping ad that it counts into it.
So, even if like, when you’re looking at impressions, it will actually show the four impressions for the four ads that show. But when it comes to impression share, it’s only calculating impression share using your best performing shopping ad.

Amy: I guess that makes sense so it’s not, otherwise you’d get really skewed numbers when you got multiple positions you could have.

James: Right, I mean the consequence of it is that some people have tried to, you know, look at their impressions and make some calculations, or projections based on what their impressions were versus what their impression share was, which you can’t do accurately, but you can do it even less accurately in this scenario.
And the other thing, and this is kind of a cool thing, is with the new interface, they’ve added this new metric called Absolute Top Impression Share.
And this is actually pretty useful. It’s the exact same as search impression share, except, it’s dividing the number of times that you showed up in that top position, the left most ad in the shopping carousel, divided by the times that you were eligible to show up for that top position.
And that’s a really valuable place to show up in, it’s like Google estimates it’s 20 percent higher click through rate there, on desk top, 25 percent plus on mobile. And so now, you can kind of see when you’re taking that position over, and this is a metric that was missing from regular search impression share. It still is, you can only see it for shopping.
So, that kind of, like wraps up what it is, and how it can be abused. I think the next question is, like what do we do with that? How can it be used, if it can be, and what should people watch out for?

Amy: Well, I think that something that’s really worth keeping in mind is what we learn from Google’s ad words definition of impression share on their page, and we can link to this in the show notes. They specifically say, keep in mind, impression share is based on an estimate of when your ad was competitive in the auction. Small fluctuations over time don’t necessarily indicate that action is needed. Changes to your bids, quality, or Google’s ad systems may change the set of auctions in which the system estimates you were competitive.
So, you never wanna have your key performance indicator be an estimate. Like, that’s just bad news, you know, especially when Google’s admitting that they’re making changes in the back and it’s going to affect how this is gonna show up.
So, I think it’s really important that we’re all clear on that. That there’s no question, this is an estimate, this isn’t a KPI, this is just something we can use. And the way we use it isn’t by giving it the most priority. It’s a pretty good measurement of, you know, if we’re trying to look at something, all the campaigns at a glance, and we’re just quickly evaluating how competitive something is, or where more budget could really be useful, that helps to tell a story pretty well.
You know, if the impression share is 30 percent, and 80 percent is lost due to, or 80 percent of that is lost due to budget or bids, we know where we can start to fix things if we wanna see that start to improve.
But what we don’t want to do is measure the health of the account based on this, because it’s just the way, like the easiest way to get a bigger impression share, a greater share of eligible impressions is to lower the denominator, rather than pump up the numerator. So, it’s so easy to game, and it’s so hard to actually get that number to where you want it to be, excluding any sort of gamification from that, just because it’s an estimate and it’s so vulnerable to adverse changes as opposed to just like, actually measuring how we are doing.

James: Right, and what you just brought up kind of brings up the point of how we can clarify a few things. So, I had been talking about how different match types can complicate impression share, how it can skew the data.
So one thing that Google does provide is some additional columns that can be added to the campaign ad group or [inaudible 00:16:12] level, and those are exact search impression share, you can look at the percent that’s lost to an insufficient ad rank, search impression lost to budget. Those are basically your keys.
Anyways, for exact search impression share, essentially what that’s saying is that, it’s the number of times you showed up, divided by the number of times you were eligible to show up, but only for the exact term that you’re bidding on. So, even if it’s a broad keyword, they’re only going to count the search queries that were exactly what your search query is.
So that helps you look at it and kind of get a cleaner idea of what you’re looking at. So, if you add both of those columns, very typically for any keyword, you’re going to see a much higher, probably, a much higher exact search impression share than you’re gonna see a search impression share.
A lot of word salad there. But, the idea is that, you can kind of exclude a lot of the noise of a lot of different search terms that can be pulled in by any random broad keyword, by looking at just when it’s matching your keyword exactly.

Amy: Right.

James: And then when it comes to those other two columns, if you look at the percentage that is being lost to budget, well, it might be because your budget is too low. Like, maybe you’re missing out on a bunch of traffic, and it’s because you’ve capped your budget.
You know, 50 percent lower than your other campaigns, or maybe you just don’t have the budget available. But, it’s good to know that that’s the reason. Now, the other column is ad rank.
Now, if you’ve lost impression share to your ad rank, than that means one of two things, right? It means that either your bids are too low, the easiest lever to pull, and unsurprisingly, the lever that Google will recommend most often, actually they’re recommend budget changes, too.
But, it also might be your ad quality. It might be the quality in terms of your ad relevance, your landing page. Actually, and a whole bunch of other things, ’cause ad rank is not just those two.

Amy: So, ad rank used to be understood as quality, score, times your bid that you would need to be competitive in the auction, right?

James: Right. And the stuff that goes into quality score has just really changed. It’s not just quality score now, it’s things like ad rank, thresholds, the context of the person search. Their location, the other ads that are showing up on the screen, a lot of stuff that we don’t get data for.

Amy: And presence of ad extensions, which factors in, but we’re not quite sure how.

James: Yeah, if you have ad extensions that are available, than that’s gonna up the likelihood that they’re gonna show your ad, just because it tends to increase the click through rate, which is really ultimately what Google is looking for the most, is they want people to click on your ad.
And so if it has a good click through rate, they’re gonna up the quality.

Amy: Right, but quality score itself, is also an estimate, and it is also not 100 percent consistent. Like, I know that sometimes people are tempted to be like, well, we always have to have 10s. Like, well, you’re not going to. You could have a quality score of a nine that’s actually, objectively, much less relevant than a different key where it has a quality score of a four or five.
Like, there’s just a lot of discrepancies, that can and will occur, and it’s just one of those things. You have to be okay with. It’s outside of our control, so we just do the best we can, we continue to try and work on it, but it’s not like you did anything wrong, sometimes that just happens when you have a system, and so just Google’s processing so many things.

James: Well, one other thing that is worth mentioning there is that, the quality score that you’ll see in the interface is kind of a stack score that’s updated every so often. But the score that’s actually used is recalculated every single auction, they call it like an ad auction quality score.
And that’s gonna take into account all those things that we’re talking about. You know, the time of day or their location, whatever. And that’s something that’s gonna change constantly.

Amy: But at the end of the day, it’s still essentially an estimate.

James: Yeah. Well, and that’s the nature of these types of things, right, is that you can use them as general indicators, but even then you can only do that once you get the account fundamentals down. If you have a messy account with a bunch of bad search terms that are acting as noise in your data, than search impression share is a worthless metric.

Amy: Yeah.

James: If you feel like you’ve set things down pretty well, and you’re looking at the exact search impression share, well, that might be a relatively safe indicator. But only for that time period, if you’ve made changes to your account, you’re comparing apples to oranges.
If you try to get too exact with comparing search impressing share over time.

Amy: Yeah, definitely.

James: So, yeah, I think that’s kind of the technical aspects of it. Do you wanna just wrap up, like what the best thing is to do next, and why we’ve done this?

Amy: Yeah, I just, I think it’s really important to understand. Impression share can be useful. It can help to tell that story of, here’s what it’s gonna take to be even more competitive. But what it can’t do is tell you, specifically how competitive you are, and it can’t tell you full coverage.
There’s just way too many things to consider for something like that. So, to the extent, you can have that talk with your clients. I guess, what I would suggest for anyone who’s in the situation of being asked to optimize for impression share as a KPI, to at least do a healthy job of pushing back on that, and explain why it might not be the best idea as opposed to just going along with it.
Like, you can, that’s your choice how you want to run your campaigns and your accounts, but it’s probably better to have everyone educated, and really get the best results for your clients, than to just listen to them if maybe they’re coming at you with an incomplete understanding of how this works, rather than letting them run it based on that incomplete understanding, it’s much better to make sure that we’re all on the same page, and that we’re making the optimizations that are really going to grow businesses and get real results, not just make someone happy because they don’t understand it.

James: A warm, fuzzy metric, right?

Amy: Exactly, exactly, that’s important too, client happiness is important, but it’s better if the clients are happy because they just had their best month ever, and not because we gave them a picture that looks nice that doesn’t really represent any actual growth.

James: Right, ’cause there’s an arbitrary increase in impression share that may have actually rendered their account worse.

Amy: Right, yup.

James: Cool, and one thing that I could put out there is that, it can be difficult to educate people about what this is, and why it’s not a great KPI. It kind of takes a little bit of work. We’ve actually spent some time putting together a document that we use to send out to clients when it becomes necessarily.

Amy: Just a POV, yeah.

James: Yeah, it’s just kind of, it helps them understand why it’s not a great metric. You know, we might alter it depending on who the client is, though we found it’s useful to kind of get that POV out so that there isn’t any misunderstandings.

Amy: Right.

James: All right, well, I think that’s it for search impression share. It was a quick episode this week, but we’ve seen more and more that this is a misused metric, so we really wanted to get out just some of the salient details about it.

Amy: Yup, all right, awesome.

James: All right, thanks so much for joining me this week, Amy, I really appreciate it.

Amy: Hey, of course. Bye.