Cross Device Conversion Rates

In an online environment that is made up of multi-device purchase behaviour it is becoming ever more essential that we understand cross device journeys and conversion rates, however ultimately for most marketers this is impossible to do accurately! Which is very frustrating, as we are all confident that although mobile visitors may not convert directly, they are still of great value. However, as they may come back to book/transact on another device, how do we look at their performance? This is something that is more and more a frustration for us and our clients. Unfortunately I don’t have the answer to cross device tracking… yet! However I have outlined my thoughts below on how we may all be able to look at and use the data we do have access to more accurately in the cross device world we now live in.

Analysing Cross Device Data

Taking all traffic for client ‘A’ over the last month, see below how we would traditionally calculate conversion rates for each device individually:

Desktop 2,784 Conversions divided by 114,672 Visits which gives us a conversion rate of 2.43%

Mobile 785 Conversions divided by 143,121 Visits which gives us a conversion rate of 0.55%

Tablet 1,979 Conversions divided by 108,530 Visits which gives us a conversion rate of 1.82%

So this is how we look at conversion which, if we compare to the same period the previous year:

Desktop – 1.60%
Mobile – 0.22%
Tablet – 1.03%

Makes it look like everything has improved year on year from a conversion rate point of view. Great right? However, surely if our theory is correct then part of the reason desktop conversion rate is up is because users have been visiting via mobile but then leaving and returning via desktop/tablet to complete their purchase, which we are not taking into account here! So shouldn’t mobile conversion be up more significantly? If you take into account the full user journey? With that in mind we should be calculating cross device conversion rates based on total visits, not just the visits to that specific device, so:

Device Conversion rate = Specific Device Conversion/Total Visits

If we were to apply this logic to the data above, the numbers would look more like this:

So why is this important?

Well, looking at the traditional breakdown of conversion rate by device we saw good growth in conversion rate across all three. Generally the desktop growth over shadows other devices because it sees good growth on what is already a big conversion rate, so therefore it would be easy to un-intentionally focus our marketing efforts on that device. However, by breaking down conversion rate growth using all sessions per device it shows that desktop has still seen growth in conversion rate, but not as significantly as tablet and then mobile, which has seen huge growth!

So with this logic, could we not push mobile activity, then look at CPA in the same way? Total spend divided by conversion per device?

I find this an interesting way of trying to look at cross device performance when taking into consideration the fact that (according to Google) 65% of decisions now start on mobile but do not end there! I hope this gives you more to think about when trying to prove the value of mobile activity.