Mobile Analytics Tracking: Challenges and Solutions

Thanks to the iPhone and Android, the smart phone market has been boosted since last year. According to a report from market researcher IDC, shipments of smart phones in the first quarter of 2010 grew to 54.7 million units, a 56.7% increase over the first quarter of 2009. As a result, internet usage via mobile phones has been steadily increasing.  The mobile web grew 110% in the U.S. last year and 148% worldwide as measured by growth in pageviews. To fully realize the potential of today’s mobile world, e-businesses are rapidly developing mobile sites and mobile content to serve an ever growing population of mobile users. It also means these companies must be prepared to exploit the latest web analytics technology to measure their mobile sites and improve their performance. However, unlike standard web analytics, mobile analytics tracking faces many challenges and needs different tracking methods to guarantee the best quality of data is captured.

Data Collection Challenges

The current web analytics data collection is based on JavaScript. The JavaScript initiates a 1px image request to an analytics service provider and the relevant information desired for an understanding of the visitor behaviour is sent along with the image request. Among the information gathered is both a persistent and a session cookie. However, although some smart phones like iPhone and Android do support JavaScript, there still are hundreds of different kinds of devices in the markets and most of them don’t support JavaScript yet.

Another issue is cookie support. If you use different analytics tools to measure your mobile site at the same time, you will be surprised by the results.  Two different tools can return totally different unique visitor numbers. These differences are because many mobile devices don’t support cookies and analytics vendors have different ways to identify mobile unique visitors.

Bypassing the issues

In order to combat the issue that some low-end mobile devices don’t currently support JavaScript execution, we have to send the image request manually instead of calling preset JavaScript methods. Fortunately, Google Analytics provides a smart solution by calling the server side snippet solution instead of sending ugly image request query string parameters. Google has pre-defined the image request server script in the most popular languages such as PHP, JSP and .Net. Users just need to download the preset script file and put a tracking snippet on the mobile site to call the pre-defined file. You can download the pre-defined file from Google Code, and then put the following snippet (PHP Version) at the end of your mobile site:

<?php
  $googleAnalyticsImageUrl = googleAnalyticsGetImageUrl();
  echo '<img src="' . $googleAnalyticsImageUrl . '" />';
?>

Unfortunately, many analytics vendors, including Google Analytics, haven’t provided any solution to bypass the cookie support issue. As a result, Google Analytics always counts a mobile visit as a unique visitor and displays inflated figures. In order to get correct visitor information, we need the persistent visitor ID. Some enterprise analytics vendors, such as Coremetrics, allow the users to send extra query string values with each tag to associate it with both a session and a cookie ID.  The cookie ID source value will be persistent and based on a value defined within the device and accessible via API or OS layer to the code generating the image request. And the session ID could be randomly generated with each device session or generated using a device session value. As a result, Coremetrics could be able to identify new visitors or repeat visitors.

Pitfalls of Current Mobile Analytics Tracking

Again, like standard web analytics, the data collected from analytics vendors is not 100% accurate. The cookie IDs generated by the device API are not always stable, and manually sending image requests do not support some high level analytics functionality such as event tracking in Google Analytics and Marketing tracking in Coremetrics.   With increasing popularity of mobile usage and high demands of accurate data, I think more improvements will be made in the near future.