By bizn_fun 
Clearly, the average would rise because more, higher value, purchases could be made via contactless, without a PIN.
But what is much harder to quantify is whether people were spending more frequently, and larger amounts, than would have been the case if they had needed to enter a PIN.
Richard Whittle, an economist at Salford Business School, says the extra convenience for consumers can come at a cost.
“If this ease of payment leads to consumers spending without thinking, they may be more likely to buy what they don’t really want or need,” he says.
He says this could be a particular issue with credit cards, when people are spending borrowed money and accumulating debt. He believes regulators should consider whether to have different rules for contactless credit cards than for contactless debit cards.
Stuart Mills, a lecturer in economics at the University of Leeds, says cash gives “visible and immediate feedback” on how much money you have, while a PIN is an “important friction point” for controlling spending.
“Removing such frictions, while offering some convenience benefits, is also likely to see many more people realising they’ve spent an awful lot more than they ever planned to,” he says.