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Saharsh Agarwal : The Impact of Global AI Overviews on Publisher Traffic User Experience

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Saharsh Agarwal conducted a comprehensive field experiment in collaboration with Ana Sen from Carnegie Mellon to evaluate the impact of Google AI Overviews on publisher traffic and user experience, utilizing a custom Chrome extension developed by Kiara Andre. The study randomized over 1,000 US-based users into three distinct groups: a control group using the standard interface, a "Hide AIO" group where AI Overviews were suppressed to prioritize organic results, and an exploratory "AI Mode" that forced conversational-only search interactions. Participants monitored their behavior for two weeks after establishing robust baseline browsing histories, revealing that when AI Overviews are triggered in approximately 41% of queries, they significantly reduce external clicks per search by about 40%, effectively cannibalizing traffic from publishers without generating sponsored click revenue. The analysis highlighted a stark contrast between the control and intervention groups regarding zero-click searches; hiding the AI Overviews reduced this metric only slightly while actually increasing organic clicks to nearly double that of the standard group, suggesting users can still find answers through traditional links when forced away from the summary box. Conversely, forcing an exclusive reliance on conversational AI led to high user attrition and lower engagement rates compared to other conditions, indicating a strong resistance among searchers to fully automated interfaces as defaults. Despite these shifts in traffic distribution, self-reported surveys showed no perceived difference in experience quality between groups, leading Agarwal to suggest that the reduction in clicks may reflect decreased search costs rather than diminished utility, though this interpretation remains debated by industry experts regarding whether users are truly indifferent or simply less aware of their reduced interaction with external sites. Beyond immediate traffic metrics, the study addresses broader implications for product discovery and consumer choice within a changing information environment where AI Overviews appear in only 12% of transactional searches despite triggering half the time overall. The research suggests that when an overview does not provide a definitive answer, search engines should explicitly justify why no conclusion was reached rather than simply displaying "no result," potentially preserving trust and aiding user decision-making regarding pricing and attributes. While the paper is praised for its credible causal inference and significant findings on traffic cannibalization—raising important antitrust concerns highlighted by recent European Commission investigations—the authors recommend softening certain interpretations of the results and leveraging available prompt data to further investigate how these AI interfaces specifically influence the informational and discovery phases of user behavior in future studies.
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Heat. Heat. All right. Uh good morning, good evening and good afternoon everybody. Uh I have the pleasure to introduce Sahar Agarwal um to our TSC seminar. He's going to talk to us about the impact of Google AI overviews on publisher traffic and user experience. Dahar, you have 40 minutes. Take it away. >> Thank you so much Kiara. Thank you so much everyone for joining. Thank you for the organizers for having me here. It's uh it's a great honor for me to be presenting my work. Uh it's a paper I'm really excited about. So uh it's a field experiment talking about the impact of AI overviews on publisher traffic and user experience. And this is joint work with Ana Sen from Carnegie Melon. So, so we'll just get started and if you have clarifying questions, maybe just feel free to ask along the way. But for more substantial questions, we can just wait for the end. So, firstly, a project of this nature requires tons of funding and support. So, I'm very grateful to ISB for funding this project through couple of different channels and also to my RAIT who has been phenomenal support throughout this project. So, now the topic of this study is Google's AI overviews. uh to this audience I don't really need to introduce what EIO views are but again just for the sake of completeness so like when you put a query on Google u you you start Google is now showing you like an AI summary uh which in most cases tends to answer the question that you're asking and so u you see you see a response you see a bunch of different links and uh these AI overviews have been a little controversial Because if you think about the nature of the search market, it is very symbiotic. Like Google is not really producing content and there are tons of content providers who exist uh and like whose ex whose existence depends on uh discovery on Google search and so the the the relationship is very symbiotic because Google provides visibility to these content producers. And so therefore uh when when users use Google, Google makes money out of ad revenue and these publishers also get traffic from Google. So therefore it's a very symbiotic sort of a relationship. However, uh there has been a shift in this relationship in in the last few years and u so there are increasing concerns around value capture uh in the search market where although producers are taking effort and incurring the cost to produce content the the concern is that search engines might be internalizing the benefit of the content production and they're sort of externalizing the cost onto the producers. So we are seeing a bit of an increase in uh the phenomena of zeroclick searches which is that a user makes a search and uh instead of referring the user to the downstream content producer search engines are answering those questions on the page itself because of which I'm I don't really need to click and so that's the that's the the question that's the tension here and uh clearly there is an antitrust angle involved because of u the value capture concern and so uh as you can imagine there's a lot that's been written about it a lot of observation studies trying to look at okay the world before AIO was world without a views queries where AIOS are shown versus queries where AIOS are not shown however uh we don't really have clear causal relationship yet and that's what we we're trying to answer and of course this issue is at the core of a lot of antitrust concerns very recently the European Commission launched antitrust investigation against Google for the very same reason that we're talking about. And so this is the kind of policy discussion that we hope to contribute to through this work. And so in this paper uh we are providing empirical evidence on this question using a randomized field experiment. And so uh we developed a custom Chrome browser and uh so this browser was built on top of webmunk by Kiara Andre uh and so it's it's an open source tool that they made that they made available. So really thankful for that. And so uh what the extension does is two things mainly. So uh the extension allows us to log passive tracking data at great granularity. And so we can we can track every single URL visited. We can track every single click made. We can track every single scroll. And in fact, we can we can track a lot of detailed telemetry data like tabs which is pressing the back button, closing the browser window and all of that. And so so the level of granularity that at which we're able to track these users is is very phenomenal. And beyond just tracking users, we can also passively manipulate the interface of any website that we like. And so what we did was uh I I'll come back to the study flow in a bit. But so we had the control interface where we just collected data without really changing anything and 36% of our users were assigned to the control group and then we had the main treatment intervention the second one which is the hide AI overview group I'll call it HIO in short. And so what we did here was that the AI overviews were hidden and everything else was pushed up in order to make the interface very seamless. And uh the third condition was a very it was an exploratory condition the AI mode condition. And how it how it worked was that when when users entered any query even on their search bar the the the browser address bar or even if they go to google.com and if they type any query they would be automatically redirected to AI mode and they could not have come out of it and as you could as you could expect like we we forced people to use AI mode and they could not have come out of it and so we expected a lot of attrition in this arm and anticipating that we we kept a small share of the split to AI mode because we wanted this uh the results from this arm to be fairly exploratory. So these are the >> Yes. >> Sorry, quick clarifying question. When you say that you can't get out of AI mode, does it mean that if you they click on all images etc that does not redirect them to the other format? >> Yeah. So actually the the example I'm showing you is not a great example because um so for the study participants all of these were actually hidden like all images video etc in the AI mode. So they could not >> for all of them for all of the treatment groups. >> No no no in in the AI mode. >> I see. Okay. >> Right. Right. So, so we didn't really want them to come out of the EM mode, but however, in in the other two groups, they could see the other buttons. Yeah, these screenshots are sort of taken post facto. Uh so now in terms of the study flow, so we we used prolific to recruit people who would be willing to install an extension. And so uh we first had a pre-screening survey. And in the pre-screening survey, we uh we asked people uh three questions. The first was we asked them what the default search engine is on the system that they're using. If they responded anything other than Google, they were uh screened out. Secondly, we asked them what is the what browser do they use on the current system. If they said anything other than Chrome and even if they said like two different browsers, which is Chrome and uh Firefox, they were screened out. So they had to use Chrome and only Chrome. So we were trying to minimize users switching to a different browser. And thirdly, we asked them what all do they use their current desktop for. And if people said that they use it only for like taking surveys because because anecdotally we've seen that a lot of these prolific workers, they have a dedicated laptop just for taking surveys. And so we wanted to screen out those kind of people because they wouldn't be giving us any useful search data. Of course, this is all self-reported. uh but they didn't know what the expected answer was. So we can just trust that they're not really trying to please us with their answers. And so uh if they passed that check then they were directed to a page where they could install the extension. And uh so we we had given a passcode on the prolific page where which they could use to install the extension and uh after that we of course this baseline should have come before the extension installation. So we had a very brief baseline survey two questions we asked them. The first question was about their trust in AI generated information coming from these AI summaries. Secondly, we asked them what com comfort with using AI tools for information seeking. That's it. And these are mainly for just checking hetroenity. So after that uh the extension automatically performed a history check. The reason we did this was that we only wanted to keep people who would give us reasonable search data in the period. And so there were a couple of things we checked for like they should have reasonable amount of u browsing activity in the last 20 days. So like at least 10 days we have some browsing data from them and we have at least 10 uh Google searches for them in the last 20 days. And also we have at least 25 unique domains. These are very small numbers just to make sure that we don't have people who don't really use their laptop for search. And so if they pass that the extension uh sort of live and uh automatically randomizes them into one of the three groups the hide group which I just showed you, the control group and the AI mode group. So the split now this is uh like we are randomizing one at a time like we didn't really have the luxury to wait for all the participants to enroll and then randomize at we had to randomize in real time and just sort of hope that the balance checks check out. Unfortunately, it did. I'll show you that. And so, once people installed the extension, uh we we observed them for 2 weeks. So, that's what we promised. But participants were told that after 2 weeks, they can uninstall the extension. And so, at the end of 2 weeks, the bonus was paid to them. And after the bonus was paid to them, an endline survey was administered. And this part was important. So, we paid the bonus first so that they could respond truthfully in the endline survey. And uh and yeah, of course, people are told that in the event that they do not choose to install after 2 weeks, we would still be possible to track some of the data. So uh so yeah, we we ended up recruiting 1065 people and uh we we checked for balance uh across basic demographics and trust and AI information. This is the baseline that we got in the survey. Trust and comfort DI tools and the three different the last three measures prior Google visits, prior active browsing days and prior unique domains. This we got from the extension itself when we were doing their browser history checks. So we have uh we have balance between all the three groups. So, so of course this is balance at baseline right and now balance at baseline uh is great but however because it's a longitudinal study uh we obviously expect some kind of attrition along the two weeks and so while balance at baseline is good we want to make sure that we don't have differential attrition across the twoe period and so the first thing that we actually track is part of >> sorry clarifying question where are these people from I should probably know from the latitude and longitude but I don't >> yeah these are all US >> US okay thank you >> okay so uh so yeah we have balance at baseline which is great so the next thing to look at is survival over time and do we have differential attrition now our intervention was intended to be very light touch like all that we removed was the AI overviews and basically nothing else changed and uh if it was truly light you would expect people not to really notice much not to make a big fuss out of it and and not uh not quit. And fortunately, that's what we see. And so day the 15th day is when the bonuses were actually paid and the the twoe period was completed. And uh we have actually pretty good retention if you look at the main treatment and the control groups. So we have over 90% retention in both of these groups. And the good thing is that although there is some attrition, uh we don't see differential attrition. The attrition is pretty much similar. However, AI mode is very different. Like it's not very hard to expect. Uh we we we sort of forced people to use AI mode for the two weeks. They could not have come out of it. Like even for a very simple simple search, they get redirected to AI mode. And so uh 60% is a retention that we saw in the AI mode. And this is something that we anticipated as well. So given the higher attrition in the AI mode, we'll treat results from AI mode as more exploratory and our main results are going to be focusing on the the show and the hide overview groups. And of course uh once the 15-day period was over, we administered the uh the the payment the endline survey and among the people who chose to remain and uh we we we switched the treatment status. So treatment became control and control became treatment. And so the reason we did that is that while it's great to have between user comparison, uh the switch lets us have within user comparison before and after the switch and in fact we can also use user fixed effects so that we can be totally sure about our results. So I'll talk about that as well. Okay. So uh so we start by first documenting the prevalence of AI overviews and given how much is being discussed about this topic we realized that people felt that this itself was uh an important contribution just just knowing how much of AI views is actually out there and so u if you look so we observe a total of 16 68,000 unique searches in our data uh over the twoe period on average we see that AI overviews were triggered in about 41% of all queries for uh and the good thing is that this is balanced across the treatment in the control groups. So it's really not as if people in the control group are putting in more queries which are likely to return any an AI overview. We don't really see that happening here. And so uh most of our analysis is going to be following this particular partitioning which is that there are queries which triggers an AIO view and that is based on some uh algorithm that Google uses and then there are some queries which do not. And now if you think about our extension it does basically nothing for these 60% of queries where the AI movies are not triggered. So there's absolutely nothing that that our extension does other than just track data. And so the only cell which is affected by the intervention is this. And so this is the cell where we actually expect to find effects. And we'll treat the AIO not triggered group as a placebo. So that's uh and of course we'll just do a very simple comparison of means uh because we have successful randomization and we'll be and this data is going to be at the search level and so we'll be clustering all the standard errors at the user level. So now talking about the main results. Uh so I'll first be talking about results at the search level. So like conditional on a search happening. Uh how many clicks do we see per search? What is the likelihood of that search being a zero click search? Uh what is the number of sponsored clicks that we see? So all of that analysis is going to be conditional on a search happening. However, there is there has been some discussion that maybe AI overviews is leading people to search a lot more. And so if that is the case, you might you might expect a shift in the extensive margin itself. And so after showing you results at the search level, I'll come back and show you results at the at the overall user level. So at the search level, so this data is at the search level. The first variable I'm tracking is a total number of external clicks per search. And so what we see is that in the control group, we see 0.37 clicks per search. By the way, these are organic clicks. I'm not uh sponsored clicks is is on is is on the third panel. And these are organic clicks basically coming from anywhere on the page. Okay? So they could be coming from the AIO view, they could be coming from the knowledge gap elements, they could be coming from the search links, but anywhere on the search page. And so we see that when we hide the AIO views the clicks per search goes up by a really large number which is 0.25. And so if I keep the hide group as the base like the status score before AI views were launched. So uh the reduction in clicks as a result of AIO views is about 40%. And similarly the probability of a zeroclick search in the presence of EIO views is 0.7 0.73. So what that basically means is that if people put in 100 searches uh and then when an AI view is triggered 73 of those searches do not lead to any click but when you hide the AI views that number drops from 73 to 54. And when it comes to sponsored clicks we don't really see an effect. Of course these numbers are really very small. So if an effect at all exists like it would require significantly more power to detect it but at least with the power that we had we don't see any effect on sponsor clicks. These are only uh conditioning on queries where the AIOs are triggered. So the next thing I'm going to do is I'm going to look at this half where the AI ovs are not triggered and we we shouldn't really see any difference in the treatment and the control groups and that's what we see. So when we when we condition on queries where the AIOS are not triggered for external clicks we don't see any difference for likelihood of a zero click search again we do not see any difference and same for sponsored clicks. Although uh one thing to notice here is that the number of sponsored clicks here are almost three times the number of sponsored clicks here. Although we don't see any any difference and so it sort of suggests that Google might be strategically choosing to deploy AIO views in some kind of queries and not the others but we don't really see effects here and this is reassuring because uh if our placebo I mean if if our extension is sort of working as it should we we don't really expect to see effects in this particular arm. So these are all results from the search level and these are all between user comparison. I've compared the the treatment and the height group. Sorry, the treatment group and the control group. So the next thing I'm going to do is I'm going to show you results from the the within user comparison. So once the twoe period was over, we flipped the treatment status for the treatment and the control users. So so those who had AI overviews hidden became control and those who had AI overviews being shown became the hype. the height group and now we compare these users pre and post switch. So the panel on top are those users who were initially in the hide group and the row in in the bottom are those people who were initially in the control group. So if you look at those who were initially in the height group before the switch they had higher clicks and after the switch this went down and we see a nearly symmetric switch for people in the control group and same for zero click search. So now this is purely a within user comparison and we have user fixed effects here. That's why these difference numbers are not really aligned with the arithmetic difference of the difference in the in the bars because we have user fixed effects when computing the differences. And so now what this is telling me is that uh even if for for whatever reason our treatment and control groups were not very comparable at least uh if we look at the same user across different conditions we see exactly the same effects. And this is very reassuring that the results that we are finding are are very causal. Okay, so this is what I have for uh search level results. The next concern of course is that uh this entire analysis is conditional on search. But what if AI overviews is leading people to search more for instance and so it's possible that clicks per search are going down. But if searches are really increasing a lot more, then it's not clear what the effect on total clicks will be. So that's what we're looking at here. So now uh this data is at the user day level. We also have user level regressions which have very similar results. So this data is at the user day level and we are looking at three different variables. The first is total number of searches made by by a user day. Second is total number of clicks coming from AI overview triggered queries. Third is clicks coming from AIO view not triggered queries. And here we see that there is no effect on number of searches. So across the treatment and the control groups, we don't see people making less searches because we've hidden the AI views. And uh at the user day level, we see an increase uh of clicks by a significant proportion relative to the control relative to the baseline and we don't see effects for queries where the EIOBS are not triggered. So, so basically it's not as if people are searching a lot more at least in the two week period. Uh in in the longer term things may be a little different but in the two week period people not searching any less or more just because we hit the AIO views. So now one narrative which has been going on is that uh okay like AI overviews are cutting clicks but but these are all low value clicks that the AI views are cutting because there there are people who land on your page and then okay who realize that okay this is not what I was looking for and who who quit very early and so we we can examine this in the data. So there are three different metrics that we look at in terms of the quality of the click. So now this observation is at the click level. We observe a set of searches from the from the main treatment group. We observe a set of searches from the control group. And we are we comparing these clicks uh on three different metrics. The first thing that we're looking at for for the click is the likelihood that uh after the click the user press the back button to go back to Google search. Now uh if you notice like we have slightly lesser observations for this one compared to these two that's because uh so if you think about a us a user using Google search uh they can either make a left click or they can make a like a right click and open a link in a new tab. We are able to track all of that with our extension. Now if you open a link in in the same tab you can press the back button and go back to Google search but if you open it in a new tab uh there is no back button there. And so so we we are tracking the back button search only for same tab clicks which is why we have slightly lesser observations. We see that and this number was significantly more than we had anticipated. 40% of all clicks coming from Google they they lead to the user going back to Google potentially indicating an unresolved search and so but we this number is not different at all in the treatment and the control groups. The second measure that we're tracking is bounds. Now bounce is a measure which has no standard definition like many different people track many different definitions of bounce. So what we did is uh we first computed the time the total time that people spent on the click page and uh of course the caveat here is that time spent on a page is a very noisy measure to capture like despite the best of telemetry data like there are always approximations involved in computing time spent. However, uh when when you're looking at short durations, it's it's much more accurate. When you're looking at longer durations, it's not clear as if someone was really looking at the screen or or if they were uh somewhere away. So, we define bounce as uh a click session which lasts less than 10 seconds and where the user did not make any navigation inside the click page. So, both of these conditions have to be true. uh I may have I may have left that website within let's say 8 seconds but if I if I made a click anywhere inside that page then that is not counted as a bounce. So bounce is uh duration less than 10 seconds and not engaging with the with the page that you've clicked on. And again we see that about 18% of all clicks were lowquality bounce clicks where the user bounced out without doing much in less than 10 seconds. However, this is not different in the treatment and the control groups. And then we also looked at overall duration and uh that is also not different. And so this is not very consistent with the current narrative that AI overviews primarily eliminate lowquality clicks. We don't really see any difference here. So this is in terms of the quality of clicks and then I told you that we had a third arm which was the EI mode arm and uh as again just reminding you that given the different given the differential attrition we won't make a strongly causal claim about this arm. However, it's just uh it's just a a nice add-on to have and so we we don't have a split here of queries where AI OBS were triggered and where they were not triggered because we don't have an equivalent of that in the AI mode. And so we are uh looking at all the queries in the control group together without the AIO view trigger not trigger split. Similarly, we're looking at all the queries in the treatment group and then we're looking at all the queries in the AI mode group. Now uh defining a query in the AI mode is a lot more complicated because it's conversational. So like someone puts in a query and then they could be putting a follow-up query. Now the follow-up query could just be a refinement, could be a follow-up question, it could be a fundamentally different query. And so we're taking a very simple approach which is that we're taking the first query which starts the conversation uh as a query in the AI mode and then uh any follow-up question which happens to that question. So any click happens anywhere all of them gets attributed to the first query. Okay. And so uh so we'll be overstating uh clicks per search because it's right now what we're saying is that if someone puts in a query on on Google AI mode and then it's possible that after two follow-ups they put a third query which is fundamentally different and now in in the entire session let's say that they make only two clicks and so we'll be saying that they made two clicks for the original query which started the session. However, uh it's actually two clicks for two different queries. So, but we are collapsing it all into one query. So, it's a simplification which is sort of overstating the clicks per search. But we see that the number of clicks in the AI mode was actually lower than even the number of clicks in the control group which was anyways lower than the height group. And correspondingly the the probability of a zero click search was much higher in the AI mode group compared to the control and the hide. And so uh so yeah this is very indicative like as search goes more and more towards conversational AI there is a concern about okay how is the future going to look like in terms of publisher traffic etc. And and we we hope that this this serves as very indicative evidence of where we might be headed. So now I'm going to show you some results on hetrogenity. So the first aspect of hetroenity which we looked at is the position of the AI overview. Now Google chooses a multi Google makes multiple choices. The first is whether to show an AI overview or not. The second choice that Google makes is where to show it. Right? So uh I'm sure you might have some experience of it. Most of the times the AIO view appears right at the top of the page which I'm calling position zero. Uh so about 88% of all queries on which AIOS are shown. AIO view is like the first thing that you see on the page and then of course there are uh there I'm defining these different relative positions. So imagine that you have you have an EIO at the top and then you have three search results below that. So the EIO view would have a position zero and then the other search results would have position 1 2 and three. There are times when the EIO view appears below search results like embedded between two different search results. So that's captured by these different relative positions. But it's a very skewed split. Most of the times AI views appear right at the top. And given the skew here, we are basically defining two splits. One is that all queries for which AI overviews appear at the top versus queries where they appear not at the top and uh these are results for external clicks. So we see that pretty much our entire result is driven by clicks where AI views appear right at the top and for for for queries where EIO views do not appear at the top we see no effects. Now of course u this should not be treated as a causal effect of position because position here is not randomized. So queries which appear in position zero might be very different from those appearing in a lower position. However, this is very indicative and I would say that this is even u this suggests that that we need more work into understanding what is it about AI overviews that is really leading to such strong effects. Is it really that that they give information that people value or is it just that they're occupying prime real estate and and uh and they're sort of cannibalizing the organic links as a result. So I think that's something which should be looked at in future research. We also look at effects by query type. So we classify the queries that users put in into three different types. This is very standard uh classification like for those who work on Google search data. Informational, navigational and transactional. Informational uh queries are those where people are looking for some kind of information online. Navigational is where they're looking to navigate to a particular website like for instance someone just puts a search for YouTube. So it's very clear that they're just trying to navigate to YouTube or and the third is transactional where uh they're looking to either make a purchase or to like download a software. So where they're actually looking to like complete an action. Uh so that's what transaction is about. And so uh we see that informational queries are the overwhelming uh number in our data. 71% of all searches are informational followed by navigational at 18% and transactional at 12 and uh yeah so Google is basically strategically showing AI overviews where it thinks it's more valuable and so AI views appear 53% of the times informational queries 6% in navigational which is reasonable like when I know where I want to go uh and AI is not very useful potentially and transactional is 15%. Just a short note like in the paper uh in the draft which was shared these two numbers were sort of flipped. There was a typo. Navigational was mentioned as 15 and transactional is six. So so just take note of that. Uh so yeah these are effects by query type and and yeah of course what we see is that most of the effects come from queries. uh although I would say that it's it's hard to rule out absence like it's hard to rule out effects in navigational and transaction queries because we don't have enough power as I said only 6 and 15% of all queries actually return AIO views. Uh the direction is there we just don't have enough power to detect effects. So next we also look at effects by topic. So query type are these are like very very broad classifications. we look at topic which is like more granular. So I have plotted two things in this in this chart. So of course many different uh topics that the queries have been classified into. So the length of the bars shows the prevalence of AIO views for that particular group and the shade of the bars shows the distribution like the the share of all searches in in the data which belongs to that particular topic. So for instance we see that arts and entertainment had the highest share of searches in the data but the highest prevalence of AIO views was for health and science. So uh so health, science, law, government like these are moreformational focused uh topics which which see significantly higher prevalence of AIO views and news, shopping, sports like events uh topics which tend to be more current, more live. I guess these have uh lower prevalence of either try to locate effects across all of these. Uh so we we see significant effects in all the topics but given that we are splitting the data a lot it's hard to compare across the different categories. So we see effects in all of them like AIO views are basically uh reducing uh clicks in every single one of these. However, it's really hard to compare one topic with the other because we don't have enough power to do that. And uh so next we uh after the twoe period, we del we delivered a bonus payment to the users and then we invited them for an endline survey and uh we had 90% response rate to the endline survey which was great. Now in the in the endline sample I'm only uh restricting this to people who had actually uh kept the extension in installed for the twoe period. If they had uh quit in between they're not part of the endline survey because we want to make sure that we are only uh measuring people who actually took part in the in in the study properly. And so uh three things that we tracked uh we asked them how was their overall ex search experience over the last two weeks. And by the way, till now people have no idea that this study is about Google search. They just think it's a general web browsing kind of study. We asked them to rate the quality of information that they found on Google. And we asked them uh to rate the ease of uh finding information on Google in the last 2 weeks. And uh the the headline result here is that at least u with with the obvious limitations of a self-reported measure, we don't see any effect at all in the three uh in the three measures between the main treatment and the control groups. Although we hid AIO views for 2 weeks, most people did not reduce the number of searches. They did not think that the search uh experience was affected. They didn't feel that the quality of information was affected. they didn't think that information became harder to find and in fact most people didn't even notice what we had done and so that says something about uh about how much users might be valuing the AIO views and so we we see a bit of a wedge here that in terms of user experience I I mean I'm sure that there is an entire distribution and so there are people who would really value the AI overviews however when you look at the average uh at least on the user experience side AI overviews don't seem to be doing much. However, on the publisher side, the cost is really high. And so, that's something to think about, which is that all the lost clicks are not they don't seem to be improving the search experience. And so, so it's coming at a at a pretty significant cost. So, uh to summarize, uh we are showing we are showing some very solid causal evidence on a topic which is very policy relevant. We are saying that AIO views are having a significant impact for publishers and wherever they appear AI views on average reduce clicks by 40%. And by the way the these numbers are expected to rise because what we what we are showing is uh clicks per search and so uh you can expect that with time the prevalence of AIOBS will increase and that has been the trend like when when we when we ran the study we saw a prevalence of 40% when we were doing some pilots which was in November of 2025 the prevalence of AI overuse was around 20 25%. And so just in that 3-month period, the prevalence went up from 25 to 40. And so as that prevalence goes up, the the downstream impact is going to be proportionally more. And uh we find that the effect was primarily driven by position zero prominence. Uh and so this suggests that there is some work required to understand like what is it about AI overviews which is leading to these effects. Are users really liking the summary, finding it valuable or is it just that they're occupying prime real estate and uh and that's what is leading to all the results and yeah users are surprisingly indifferent to the presence or absence of AIO views. But yeah, users are extremely resistant to AI mode as a default. So we also felt this was an interesting result because there's a lot of conversation about how it might be the end of Google as we know it with the rise of chat GP etc. However, it seems that a as a default uh people are resistant to a fully conversational AI interface and so the standard Google as we know it is probably here to stay for some time at least. So that's all that I had. Uh I'm happy to take questions and hear your thoughts. Thank you. >> Wonderful. Thank you so much Sah. Uh now Dante you can you have five minutes to help us start the reflections. And for the others if you have questions uh that you don't want to ask directly uh you can uh uh put them in the chat and I will ask them. >> Great. Um hi everybody. I'm Dant at Columbia Business School. Thanks for inviting me to discuss this paper. Congratulations to the authors. Uh I think this is an important and very well executed paper. An important question. the the the design is very clever. So it was nice to read and learn a lot. So now my job is uh is to push on I think the interpretation of some results and also high level open questions and I want to do that uh through the lenses of the main stakeholders in this market. So the first is the search engine and the consumers and then also the publishers and the brands. So first let's take a perspective of the search engine as well as the consumers together. So um one of the last results that was shown uh and is also the headlines of the paper is that the overviews divert traffic without much improvement into uh the user experience. Um so this is actually my only push back a little bit. So I want to gently push back on this second part of this claim. Uh so the conclusion about the user experience not going up or you know not moving rest on this stated preference survey. um and uh it's based on this satisfaction score, right? But I think actually if we look at what people do, they click less, right? They accept zero click answers. So if we think about this in terms of reveal preference, then this might actually imply lower search cost. And so people find what they need without paying the you know the click and scroll tax. So the behavior I think it's consistent with the utility going up um even if satisfaction scores stay flat. Okay, so it's a different interpretation uh which I think is is important. So I would be I would be careful concluding there's no benefit to users from that survey based results. And if we think about online reada platforms in general, reductions in clicks per search normally reflect improvements in search efficiency. And so that logic can apply in your context too, right? So perhaps you can look at the time to find the answer metrics or task completion time metrics or measures and I think those would speak directly to consumer welfare more than the survey. U so if we look at the consumer side only I think there the deeper welfare question isn't just how many links they click but actually what I end up consuming. Okay. So given that in your context most searches are um informational, the question I think is do consumers read different information from different sources uh with different length or authority compared to the prei word. Sorry. So I think perhaps you can look at what is cited in the overview and compare the sources cited there against the top rank results uh organic results. Right? For example, I would be curious to see whether more word of mouth sources are cited there versus established news outlets. And I think you have the data to answer these questions and you you can do that. So now let's switch to the publisher side. I think for publishers that's where the results are strongest very convincing. Uh what I would do I would frame the paper more explicitly around the type of good that is consumed here. So in the footnote you have the thatformational queries account for 71% of searches and that's where most of overview trigger rates is is the highest. Uh so I think the results speak directly to publishers. So these results speak to them. Uh so this is about news content information consumption right so I would make that ex that footnote much more salient in the paper more prominent rather than just you know keeping in a footnote. So u the other question then on publishers is about the the overview itself as a channel right so the question there connects to my previous comment so are the sources cited in the overview uh the same as those cited in top rank organic results or are they something else where basically overview borrow from right this is critical right do users click uh and the links in the overview that are provided there actually wasn't clear to me if the outbound clicks also include the uh links that are provided by the overview. Um, and you know, if being cited in an overview recovers some of that traffic that instead would go to the to the organic results, then you can reframe the story from a pure cannibalization toward a a GEO game, right? Generative engine optimization perspective. And I think this is actually an important question, a deep question in digital marketing, right? So this opens the chance to uh understand whether GEO efforts for brands and for publishers pay off, right? So where basically the overview site from right does it borrow from the organic results or not and then finally you have the brand side and then I'm done. So the brands you know the commercial transactional side uh so you have a clean null sponsor uh clicks result which is interesting but I think that's kind of partly might be mechanical and I think you can elaborate on that. Uh so the overviews in fact in that side are are less common for transactional queries. uh you you you said it you know 50% trigger rate out of 12% of searches that are transactional. So I think for those searches where the sponsor link matter the overview mostly isn't there right is not there much much of them. So what I would do I would make an argument explicitly rather than just presenting the no result and I would try to justify that that no conclusion more carefully. uh and also for brands and this is my last point for brands and consumers. I think the first order question in this era is whether these new search environment affects discovery and choice. Okay. So what products consumers buy, what prices they pay, what attributes they look for. So this is an open question, right? Um and I'm not I'm not sure that you should answer this question in this paper, but maybe you have the data. So if you can say anything about for example studying the prompts consumer writing the eye mode more explicitly trying to understand the discovery phase for products for brands I think that would be really valuable in this domain. Okay so to sum up I think this is a great paper uh do you have credible causal inference and causal evidence uh the implications for traffic are very important. So suggestions are mainly soften the interpretation of some of your results and maybe exploit the data to answer question on the information and also on the discovery phase using the prompts that you have the prompts that that you have and thanks a lot for inviting