If your AdWords account contains multiple campaigns which also includes mobile targeted campaigns, then you might notice that your reported cost per conversion is different from the expected cost per conversion.
Rest assured, this is not a discrepancy or a mathematical error by Google. There is, in fact, a very simple explanation for this, as given below.
Conversions (1-per-click): 432
Cost per conversion: $188.31
On calculating the cost per conversion as per the usual formula i.e.
cost per conversion = cost/conversion = $86,464.81/432 = $200.15
Now, our cost per conversion ($200.15) doesn’t match the reported cost per conversion ($188.31). On contacting our AdWords representative, we came to know about some new information which is explained below.
Cost per conversion does not always translate into cost divided by conversion. Calculating cost per conversion is slightly more than simple division because not all clicks and their associated click cost are eligible for conversion tracking reporting. As a result, the numbers you see in the interface might be varied than the ones that you would get by dividing the cost column by the conversion column.
So let’s look at the all time numbers with this in mind again
Reported Total Cost: $86,464.81
Reported 1-Per-Click Conversions: 432
Reported Cost/Conversion: $188.31
Expected Cost/Conversion: $200.15
Ineligible clicks (from many mobile devices – not counted in the conversions – doesn’t mean that they are invalid or malicious) are not included in the cost for this calculation. So as per the reported statistics
$188.31 * 432 = $81,349.92
This means that $81,349.92 came from eligible clicks for this account that are counted in the conversions and the remaining $5114.89 came from ineligible clicks, most likely from conversions performed on mobile devices.
Since the cost per conversion is a very important aspect of every ad campaign, it is important to ensure that one is not missing anything. Also, it is advisable to keep some room for possible (and unavoidable) errors. Since there is no immediate solution, it is best to have a margin for such situations.
Can you think of a solution to this? Let us know your thoughts in the comments below!