Mobile devices account for 24.5 per cent of total paid search spend and 27.8 per cent of total clicks in the UK, according to a report from Kenshoo.

While smartphones account for 11.5 per cent of search clicks, they only make up 7.8 per cent of spend. Its a similar story in the US, where smartphones account for a slightly lower nine per cent of clicks – but, crucially, for just five per cent of ad spend.

 Tablets fare much better in both markets. In fact, their share of ad spend (16.7 per cent) narrowly exceeds that of search clicks (16.3 per cent) in the UK. In the US, tablets account for 10 per cent of clicks, and nine per cent of spend.

“Advertisers should be assessing the value of mobile clicks in alternative ways, because you can’t expect a phone to deliver the same rate of direct online sales as devices with bigger screens that are typically used in the home,” said Kenshoo CMO Aaron Goldman. “It’s imperative to track and optimise conversion events like phone calls, app downloads, check-ins, website registrations, store locators. These are KPIs we should be using to measure the effectiveness of phone clicks.”

Meanwhile, CPC (Cost Per Click) on the devices has risen to £0.20 for phones and £0.30 for tablets – the latter equal to the value on PC.