Learning about a new report from Google AdWords does not make most of us sit up and listen. Struggling already under a mass of data, finding out about one more set of metrics is not something most people celebrate. Which is a shame, because most reports in AdWords are there to help you avoid making bozo mistakes with your ad spend.

For instance, once properly configured, AdWords Conversion Reporting allocates orders or enquiries directly to the keywords you buy clicks for. If you fail to look at this reporting, you may as well be using intuition to tune your account.

In some cases, applying the information in Conversion Reporting is all that’s needed to get your AdWords account to succeed. Ad clickers arrive, look around and buy or register during the one visit – nice, clean, simple and relatively straightforward.

However, when it comes to costly products, visitor behaviour may be very different. They may jump in and out of your website a number of times before deciding to buy. Whether you allocate the sale to the start, or the end, or divide it between the various elements of traffic, is a question of attribution.

People may also interact with your advertising during such a sequence of events in a variety of ways. A comfortable sofa and smartphone screens of expanding sizes have a lot to answer for here.

For example, people may browse on their phone in the evening, between ad breaks, find your ad and click. Fortunately, they like what they see, but damn, the credit card is in the car – so no sale, but a reminder is set for tomorrow at the office.

Next day our potential buyer forgets the name of your website, so searches and finds your paid ad again – this time on the office computer – and clicks again. Thankfully the price is unchanged, the item is in stock and the purchase is made.

Sound unique? Google reports that six out of 10 internet users in the United States do exactly this – start their shopping on one device and finish on another.

The image below from Google shows the percentage of cross-device search impressions for different industries.

If you tuned your AdWords account in a standard way for the scenario outlined above, you would celebrate the conversion and promptly allocate it to the office hours click from the desktop computer and shift your budget from mobile ads to desktop.

Thankfully though, the new cross-device attribution reports from AdWords can help you avoid this mistake.

Borrowing the pic from the Google post below, you can see how it operates.

The above image shows how many sales were started on a phone and finished via another device by way of something called the device assist ratio. This means that if your mobile assist ratio was five, then for every conversion you achieved on mobile, another five were started on mobile but completed on other devices.

Accessing reports like these will make it easier to see the true value of your investment in mobile advertising.

A lot of people question the value of paying for visitors who view your website via a screen size that always converts at a lower percentage than its larger desktop alternative. But maybe mobile could be starting a lot more than it converts.