Google AdWords Conversion Tracking Fails On Mobile

By January 17, 200817 Comments

Google AdWords conversion tracking uses JavaScript and HTML code that is placed by advertisers on their website’s conversion (customer acquisition) page, to track which user clicks have resulted in a conversion. This data is then reported back to the advertiser in the form of the number of conversions per keyword. This system fails on mobile devices and gives incorrect data.

A vast number of mobile phones do not allow JavaScript to run on their browsers. Furthermore, even with those that do allow JavaScript, many do not allow cookies. In fact, a number of mobile network operators block cookies as well as session details from being passed on to third parties such as Google AdWords.

Without cookies, the vast majority of conversions resulting from AdWords ads on mobile devices will go undetected. This is a serious issue, as it implies that the ROI calculations many mobile advertisers make for their campaigns will be far from the actual figures.

Not only is this a serious problem for Google, who has traditionally bragged about the exceptional accountability and reporting capabilities of its advertising platform, but it is also one that cannot be solved by the search giant.

Google needs to either find a better, more innovative way to provide accurate conversion tracking for mobile ads, or advertisers will shrug their shoulders and accept it as a flaw till a better, more reliable system is introduced, probably by a network operator.

An account manager at Google AdWords has confirmed this is the case. Her reply to our query is quoted below:

A significant percentage of mobile browser and carrier combinations do not support cookies. Google adds cookies to a user’s mobile device when he or she clicks on an ad to track conversions. Therefore, if users are using mobile browsers or carriers that do not accept or support cookies, they will not be included in your conversion tracking statistics.

Additionally, cookies on mobile phones expire faster than the ones created for PCs. Therefore, a significant number of conversions for your site may go unrecorded after a certain period of time. When viewing conversions for a specified time period, note that conversions are assigned to the date on which the ad click occurs, not the date on which the conversion occurs. In addition, we will not be able to report conversions for users who disable cookies.

Conversion tracking is also not supported when users disable images on their mobile phones.

Although Google cannot record every conversion due to the reasons mentioned above, your conversion rate, cost-per-conversion, cost-per-transaction and value/click are adjusted to reflect only those sites from which we can track conversions.


The post has been updated to clarify that the lack of JavaScript support on a mobile device is not a problem in and of itself. The problem lies in the cookies being rejected by mobile operators. Since the time of publication of this post, Google has updated its conversion tracking platform, and now offers an improved solution for conversion tracking on mobile searches.


  • Larry Larmor says:

    Actually there is another problem with Google’s system for analytics. It can’t distinguish between one user clicking your ad ten times or ten users clicking it once. Surprise surprise that Google makes money on every click – so its easy to guess that Google won’t be fixing their analytics any time soon….

  • AccuraCast says:

    Hi Larry…. just to clarify, the problem this post is talking about is not with Google Analytics but specifically with the Conversion Tracking JavaScript used with Google AdWords, which tracks the number of visitors that took a specific action e.g. bought something on the site.

    For most site owners it won’t matter too much then, if the same person came in 10 times from Google if each of those ten times they bought something, which then gets recorded as a conversion.

  • orangewed says:

    is some one actually providing this kind of tracking software. what about the ip address. is tht not a good enough way.

  • AccuraCast says:

    Individual IP Addresses usually get hidden by mobile operators. So everyone from Orange, for example would show the same IP group, making it impossible for AdWords to distinguish which user (or which keyword) led to a conversion.

    We have been informed that a well-known mobile solutions provider will be offering this service in the very near future, and we will announce it on our site as soon as the information is made public – so watch this space!

  • Darragh says:

    Google Adwords actually provides conversion tracking code for mobile XHTML pages which does not rely on javascript. This code still does depend on cookies, but your point about javascript support being required is mistaken.

  • AccuraCast says:

    The information is based on conversations with Google in Jan 08. Since then, the conversion tracking system has been overhauled.

  • Darragh says:

    Although the google conversion system has been recently overhauled, WML conversion tracking code – which does not require Javascript – has been available since 2007.

  • AccuraCast says:

    @Darragh Could you point us to where on Google AdWords you obtained WML specific conversion tracking codes?

  • Darragh says:

    Campaign Management -> Conversion Tracking -> Create an Action -> Conversion page markup language -> wml

  • AccuraCast says:

    @Darragh: as pointed out earlier, this is on the updated conversion tracking system. The old conversion tracking system did not have any provision to specify website markup language.

  • Darragh says:

    Yes, the old system did have the capability to specify the website markup language. I’ve been using WML conversion tracking code since mid 2007. I cannot point out exactly how the language was selected in the old system, but it was much the same as in the new system.

  • AccuraCast says:

    Lucky for us, Google has not updated all their documentation. If you look at the instructions in their learning centre, you will see the old conversion tracking code:


    It is JavaScript-based code, and the only choices offered to advertisers are security level and language (English, French, etc.)

  • AccuraCast says:

    Also uploaded a screenshot of the above-referenced article, in case Google does get round to updating its course:

    Screenshot of Google AdWords Conversion Tracking lesson

  • Darragh says:

    The converion code you posted is just an example. Although, I admit there is no mention of WML support in the docs that you posted a link to, I can assure you WML has been supported since mid-2007 at least. I’ve been using google WML convertion tracking code on a mobile site for about a year. Furthermore, if you were to actually read the sample converion code that you went to the bother of taking a screenshot of, you would have noticed the noscript tages, which means the code would word even in a browser which does not support javascript. The code in-between the noscript tags is essentially very similar to the WML code which i’ve been using all along. I don’t understand why you continue to deny that you made a mistake in your original article.

  • AccuraCast says:

    @Darragh thanks for pointing out the bit that is confusing. You are right in stating that JavaScript is not the problem in itself. It is the cookies deposited by the script that are a problem on mobile devices. The post has been updated to reflect this.