The ROI Revolution BlogAdWords Conversion Tracker or Google Analytics.... Which One's Right?June 8, 2007
The short answer? They're both right, although neither one is perfect. This is of course assuming you've set them both up correctly. How can this be? We'll, I've attempted to put my unfortunate artistic skills to the test to try and clear up this puzzle. So here's the story: Let's say you have AdWords Conversion Tracker set up on a specific receipt page. You also have that page defined as a goal within Google Analytics. When you look in AdWords, you see that a specific ad campaign had 20 conversions at a conversion rate of 5%. When you look in Analytics, however, that same ad campaign was only responsible for 13, with a conversion rate of only 3%. Huh? When you look at how the two systems track users and conversions, the answer to how this happens becomes apparent. Let's look at two possible scenarios for a conversion: Scenario #1: The user converts after clicking on an AdWords ad to get to the site. 
In this scenario, all is well with the universe. In both cases, the user is said to come from the Google ad they clicked on. In this instance, a conversion will be registered in both Google AdWords and Google Analytics for the specific keyword. Scenario #2: The user initially gets to the site from an AdWords campaign, but only converts later after coming back to the site from another source, like a Yahoo! organic search. 
Here's where the differences become apparent. On the first visit from an AdWords ad, both Analytics and AdWords will set a cookie that marks the user as coming from the paid Google ad. However, if the user does not convert initially, but comes back a second (or third, or fourth) time from a different source (Yahoo! cpc ad, banner ad, email, etc.), things get sticky. Upon the return visit, the AdWords cookie will remain the same, but the Analytics cookie gets overwritten. If a conversion then takes place, it will show up in AdWords as coming from a keyword, but it will show up in Google Analytics as coming from the new source. Neither one is wrong, it's just a different type of data. So here's the bottom line. Comparing the data in AdWords to that in Analytics is a little like comparing apples to oranges. AdWords will track users back to the initial keyword (only for google cpc sources), while Analytics will attribute conversions to the latest source (for all sources/keywords)The data not only might not be the same, but will not be the same. So does this mean that AdWords will always report more conversions than Analytics? Nope. Because the Google Analytics cookie will not be overwritten by direct visits, if you have a site where someone who comes from AdWords can bookmark your site and return for multiple purchases, Analytics might actually report more conversions than AdWords. Well, hopefully some of that made sense. Don't expect the conversion numbers in AdWords and Google Analytics to be the same. They won't be, and that's ok.
Google Analytics for Online Advertisers Permalink | Comments ( 24 ) | TrackBacks ( 0 ) Filed under: Analytics Posted by Shawn Purtell, Senior Web Analytics Engineer at 4:34 PM CommentsZack said: I've always wondered why. Thanks for wading through the buckets of *stuff* to come out with the goodies. Shawn Purtell said: @Zack: Thanks! We do our best. I think I've ruined about three pairs of wading boots this week :) Michael Harrison said: Heh. You definitely get the award for best image in an ROI blog post this year, man. Christoph Gummersbach said: Hi Shawn, if you consider day-by-day analysis - is it correct to quote that Google Analytics generally measures the day of conversion, Google Adwords Conversion Tracking instead measures the day of the click which lead to a conversion up to 30 days later? Shawn Purtell said: @Christoph:, I'd say generally that's true due to the way both systems work, but again I strongly caution against comparing the two sets of data.
Alan said: Hi there Shawn, Nice work showing the differences. Just for the sake of completedness, I would add 2 little elements: 1. If the second visit is from a "direct" source (typing the URL in directly or through a bookmark) rather than another organic source, then any conversion during that visit will be attributed to the previous AdWords visit within a 6-month period (hence the _utmz cookie having a 6-month expiration date) and therefore would count for the AW click in both CT and GA. 2. Another potential source of difference between conversion rates, is the fact that Conversion Tracking uses a 3rd-party cookie whereas GA uses a 1st-party one. Just my two cents' worth. Seeing as this is my first post, I would like to seize the opportunity to thank you for the incredible quality of your blog. This is a great resource for GA. Alan Alan said: Oops... Sorry, I read the post too fast. I hadn't seen you'd mentioned the direct visit scenario. Shawn Purtell said: @Alan: First of all, thanks for your kind words. Second, thanks for pointing out two things that are absolutely true. I touched on the first one, but your comment really spells it out nicely. And #2 is really what makes this whole tracking process different. Thanks for pointing it out directly. Thanks for reading! Kim Kelsey said: Shawn, I'm a newbee. I did not set up the champain, but now I am responsible for the reports and recomendations. This issue has been driving me nuts!! Thank you, thank you for clearing things up. I understand it now. Shawn Purtell said: @Kim: I'm glad I could help! Don't feel bad about being confused about this issue - we've been getting a ton of questions about this and I thought I might try and help clear things up. Thanks for reading! Everything Furniture said: GREAT info, I might also add that this is also why other marketing, like shopping engines, show different conversions and info than are reported in GA. Shawn Purtell said: @Everything Furniture: This sort of thing is exactly why comparing different tracking systems (including shopping engines and big expensive solutions) is a risky business. You're better off comparing one system to itself (unless you know they are supposed to track in the same fashion). It's also the reason why it's helpful to have different kinds of tracking, because one system may catch something another misses. Jesse DaCosta said: Hi guys, quick technical question, I understand that for Conversion Tracking you only need to put the code on your conversion / receipt pages but would you put the code above or below the GA script if that already exists on those pages? Thanks! Shawn Purtell, Senior Web Analytics Engineer @Jesse: The answer is the order doesn't matter. The two scripts are completely independent, so just make sure they are both there, and you're all set! Jeremy said: Question, I have a situation where i have 4 websites all with analytics and adwords campaigns. These sites link to another url inorder to complete a purchase. On the other site i also have analytics and a conversion tracking script on the thank you page after successful credit card transaction. I just set this up and am wondering if my adword accounts are going to register the conversions since the conversion script is located on a different url. for example: Any one know about this? Thanks Shawn Purtell, Senior Web Analytics Engineer @Jeremy: AdWords uses a third-party cookie, which basically means you can track conversions across several different domains without a problem, as long as the conversion occurs within 30 days of the AdWords click. For Analytics, you will get conversion numbers and rate, but these conversions will not be attributed to the correct source unless you've implemented cross-domain tracking, which you can read about Here. Adam said: THANKS. I've been hunting around to find out how Google joins the conversion to a specific keyword. What you've said "Adwords uses a third-party cookie ... cross domains" finally explains it. However, can you tell me HOW they do that? I though that browsers had a security feature that only allowed the cookie to be written for a specific domain. How does the Adwords cookie really work? Many thanks. Shawn Purtell, Senior Web Analytics Engineer @Adam: I can't tell you exactly how it's done (I'm not Google, after all), but the most common browser settings, in both IE and Firefox, do not block the type of third-party cookie Google uses, although you certainly could block it if you know how. The cookie itself gets set (for search anyway) while you are still on the Google domain, so in that sense, it's set most of the time as a first-party cookie. After that though, on the conversion page, the script does need to access this cookie in order to register a conversion. You'll notice in the conversion script that there is a call to an image file. This allows Google's servers to match the user up with the cookie that was initially set in order to get data within AdWords. Beyond that, I can't really go into specifics, but I hope that helps a little. Thanks for reading! Raina said: Question : What happens when the first visit is from an AdWords ad in which the user does not convert, and then the same user clicks on an organic listing and converts on the site? Flip Video Camcorder said: I don't think GA will overwrite cookies when you search from URL Shawn Purtell, Senior Web Analytics Engineer @Raina: The default for Google Analytics will attribute the conversion to the organic listing. By default, Google Analytics reports on the most recent source (unless it's direct). Shawn Purtell, Senior Web Analytics Engineer @Flip: That depends on what you mean by 'search from URL'. An organic search will overwrite your cookies. The only things that won't overwrite your source are a direct type in of your URL or a bookmark. adam said: Riddle me this: Adwords tells me i have paid for 6982 clicks Analytics sais so are the direct ones also rom google cpc ? Shawn Purtell, Senior Web Analytics Engineer @adam: It sounds like you have an implementation problem. It could be that both direct and organic traffic really should be cpc. In order to make sure things are set up properly: 1. Make sure the GA code is on the AdWords landing page. I recommend checking out the official Google training video on the subject. Post Your Comments |
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