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When importing Google Analytics e-commerce transactions into AdWords, what happens to conversions that take longer than 30 days to convert?

 

The engineering team at Finch has been doing a lot of work recently involving both AdWords and Google Analytics. Both applications have their own way of tracking conversions. To setup AdWords conversion tracking, you need to add a javascript snippet to your website’s conversion pages (for example, the order confirmation page for e-commerce transactions). Likewise, to track e-commerce transactions in Google Analytics, you need to add a different javascript snippet to your conversion pages.

It is perfectly fine to have both AdWords and Google Analytics conversion tracking javascript code running on your conversion pages at the same time. This will allow you to see conversion data in AdWords as well as in Google Analytics. There are some differences in the way that AdWords and Google Analytics track conversions, though, so expect discrepancies between what you see in AdWords versus what you see in Google Analytics.

One of these differences between AdWords and Google Analytics conversion tracking is the length of time that is allowed between a user’s initial click on an AdWords ad and the conversion before Google will “forget” about the initial ad click. Once the initial ad click is forgotten by Google, the conversion will no longer be attributed to the AdWords ad click. AdWords will only attribute a conversion to an ad click for a maximum of 30 days, while Google Analytics is configurable, but will track conversions for 6 months by default (the default expiration of the __utmz cookie is 6 months). Suppose you had both AdWords and Google Analytics conversion tracking enabled, and a customer clicked on an ad and visited your site on May 1 and subsequently converted on June 15. Google Analytics will attribute the conversion to the AdWords click on May 1, but AdWords will not track the conversion at all since it occurred more than 30 days after the initial ad click.

This is all well documented in Google’s AdWords and Google Analytics documentation and other places on the web, but what if you implement Google Analytics conversion tracking and import your conversions from Google Analytics into AdWords? Will conversions for the last six months now appear in AdWords as they do in Google Analytics, or will AdWords only import conversions that converted within 30 days of the initial ad click?

Google does appear to answer this question; “AdWords cookies expire 30 days after a customer's click, while Analytics uses a cookie that lasts six months to two years. That means if a customer completed a conversion 31 days after clicking on an AdWords ad, the conversion wouldn't be recorded in AdWords but would be in Analytics.” However, does this statement apply when (A) a site implements both AdWords and Google Analytics conversion tracking or when (B) a site implements Google Analytics conversion tracking and configures AdWords to import the conversions from Google Analytics? A very careful reading of the Google support page appears to indicate that they are talking about the latter case (B) (we already know the former case (A) to be true). However, the Google documentation just wasn’t quite clear enough for us, so we just weren’t 100% sure.

We realized that we had integrated deeply enough with both the AdWords and Google Analytics APIs that we could perform an experiment to find the answer. In this experiment, we took a website that had implemented Google Analytics conversion tracking only (no AdWords conversion tracking) and had configured their AdWords account to import these Google Analytics conversions. We then used both the AdWords and Google Analytics APIs to retrieve conversion data for a 4-month period. A careful analysis of the data revealed that conversions tracked by Google Analytics that take more than 30 days to convert from the initial ad click are apparently not imported into AdWords.

We used the Google Analytics API to download the following data:

  • Transaction id (order id)
  • Conversion date
  • Number of days between the adwords ad click and the conversion
  • Conversion amount
  • AdWords campaign, Ad Group, and keyword id for each conversion

Likewise, we used the AdWords API to download this data:

  • Click date
  • Conversion amount 
  • AdWords campaign, Ad Group, and keyword id

Unfortunately, it is not possible to download the transaction id through the AdWords API--you can only get a daily summary for all conversions with a campaign, Ad Group, and keyword.

Google Analytics attributes a conversion to the visit date of the conversion. AdWords, on the other hand, attributes a conversion back to the date of the ad click. Since we are trying to compare conversions reported by Google Analytics with those reported by AdWords for a given date, we must convert our Google Analytics conversion dates to use the click date as the conversion date. To accomplish this, we subtract the number of days between the click and the conversion reported by Google Analytics (using the daysToTransaction dimension). We found that doing this gets us really close, but we found that in some, but not all, cases the AdWords reported click date was a day earlier than our Google Analytics computed click date. Unfortunately, this means that we can’t simply sum up the value of conversions for a given date from AdWords and Google Analytics for a given campaign, Ad Group, and keyword.

Although AdWords doesn’t provide access to the transaction id from Google Analytics, we looked at all of the Google Analytics conversions that took longer than 30 days to convert and compared with the AdWords data for the same campaign, Ad Group, and keyword. We found many Google Analytics conversions that took more than 30 days to convert after the ad click but had no AdWords reported conversion value ever for the same campaign, Ad Group, and keyword.

We did the same analysis for all conversions that converted within 30 days. This time we only found one case where Google Analytics had a conversion, but there was no conversion value reported for the same campaign, Ad Group, and keyword in AdWords. This may be due to an invalid click that is recorded by Google Analytics but ends up filtered out by AdWords.

The following tables contain conversion data for 7 different keywords and compare the data between the AdWords and the Google Analytics results.

In the 2 tables below, you’ll see two conversions for the same campaign, Ad Group, and keyword for which the AdWords click date and Google Analytics computed click date are identical, so the value for both systems is identical.

 

Below you’ll see two conversions for the same campaign, Ad Group, and keyword for which one conversion took more than 30 days to convert, so it is not imported into AdWords. Furthermore, the AdWords click date for the conversion that took 29 days is reported one day earlier than the Google Analytics computed click date.

 

Following are three conversions that converted within 30 days of the click date. The AdWords click date is different that the Google Analytics computed click date for one of the conversions.

 

Below you’ll see three conversions for different keywords that took longer than 30 days to convert. None of these are imported into AdWords because AdWords doesn't import conversions that take longer than 30 days to convert.

 

In the end, it appears that our reading of the Google documentation was correct--since we found many conversions that took greater than 30 days to convert that were not imported from Google Analytics into AdWords, but only one conversion that converted within 30 days that was not imported into AdWords. We believe that AdWords simply doesn’t import conversions from Google Analytics that take more than 30 days to convert.