Google AdWords Conversions not matching database entries

Question

I've just set up a tool on a client site that users can use to request a quote from our client. To do this the user lands on a form page, fills in their details, submits and then lands on a thank-you page. Pretty basic.

I set this process up as a goal in Google Analytics, using the destination type goal: "begins with /thank-you" and shared that goal as a conversion in Google AdWords.

I decided to run a few Google AdWords ads to promote the tool. I also wanted to double-check the conversion data that AdWords gives you so I set the destination URL in Adwords to www.example.com/form-page?adsrc=adwords1 (2, 3, 4 etc. for each ad) and I configured the DB so that there was a column that tracked which URL the user was on when filling in the form (this would be the column I counted to get the number of conversions that came from AdWords so I could compare)

Further to this, I made sure that the initial URL parameters that the user landed on were stored in the session so that if the user browsed to other pages and came back to fill in the form later, it would still attribute the conversion to AdWords.

I tested this thoroughly on a staging and production environment and everything was working correctly.

I ran the campaign for a week and when I checked, the conversion results in the Data Base vs the ones coming from AdWords are wildly different. The DB tells me I've had 5 conversions while AdWords gives me 21.

Is there anything in the way Google uses its gclid that may be causing this issue? Or is there a problem with the way I've set up the measurement structure?

Answer 1

This can be caused by few things, but I think this is the GA/AdWords issue, more than your DB/session set-up.

Gclid shouldn't influence your goal, since it is used only for AdWords/Analytics interactions, Goals should not be affected in your set-up. https://support.google.com/analytics/answer/2938246?hl=en

Probable cause: If your goal set-up only contains "begins with /thank-you", isn't it possible, that you are counting all the sessions which reach thanks-you page? Not just AdWords?

Solution: if you need to count conversions in AdWords (for performance improvements), use AdWords conversion code at the same page, this counts only those users, who clicks an ad and reach your thank-you page in x (default 30) days. Be sure to count only unique conversions (users by cookie).

Differences between GA/AdWords conversion count: https://support.google.com/analytics/answer/2679221?hl=en

Answer 2

Google attributes conversions to the last marketing channel, where direct visits do not count as a marketing channel (if you look at their attribution flow visualization you see that the penultimate step is to check for existing campaign information for the user). So GA might overcount Adwords visits (or other campaigns) and conversely shows fewer conversions for direct visits.

On contrast your database probably records the last traffic channel without an elaborate attribution model, so it will show less campaign traffic.

Also IIRC the adwords interface records the conversion for the time of the ad click, not the actual goal conversion, so the timeframes for the conversions differ.