Put it this way. Last year, UK GDP was £1612bn in current prices. With a population of 64.1m this gives us GDP per head of £25161. With the exchange rate averaging $1.57 last year, we have GDP per head in dollars of $39503. US GDP (pdf) was $16768.1bn spread over 316.3m, giving GDP per head of $53013. These are close to Fraser's numbers.
One reason for this difference is simply that Americans work more; the OECD estimates that the British work an average of 1669 hours per year whilst Americans put in 1788.
If we look only at wages, though, things look very similar in the UK and US. The ONS estimates that the median full-time male wage was £556 per week in 2012, whereas the BLS estimates that the median full-time male worker in the US got $860. At an exchange rate of $1.57, these are very close. This is quite consistent with US GDP being higher, though, to the extent that non-wage incomes such as profits and the self-employed are greater, and to the extent that US earnings are higher because of higher wages at the very top.
But what about the cost of living? In many respects, this is lower in the US, which means that whilst the typical wage-earner brings in roughly the same in the UK as in the US, his money goes further in the States.
Housing costs for sure are lower. The median house in the US costs $222,900 or £134277 at today's exchange rate, whereas Lloyds Banking estimates the average UK house to cost £186322 (pdf) (yes, there's a difference between average and median, but I doubt this explains all the gap).To be more precise, you could get a four-bed house with five acres in Little Rock, Arkansas for the price of a one-bed flat in Hackney.
- 12 eggs cost £3.09 in the UK but $1.95 (£1.17) in the US.
- A gallon of milk costs £3.68 in the UK but £2.34 in the US
- 1kg of beef mince costs £7.96 in the UK but £5.15 in the US.
- 100g of coffee costs £2.78 in the UK but 67p in the US.
A comparison of prices at Amazon.com and Amazon.co.uk reveals a similar pattern. For example, a 160GB iPod costs $259 in the US (£156) but £175 in the UK. And a quick glance suggests car prices are also lower in the US. The US isn't the home of the free, but it is the home of the cheap.
Not all comparisons are so favourable for the US - there's the not inconsiderable matter of health insurance, for one thing, and Harvard's a darned sight more expensive than Oxford.
And of course, the cost of living is only part of what makes a place desirable to live in: some of us think it a good thing that the UK's police forces don't model themselves on the Islamic State, for example.
Nevethless, the point is that Fraser's claim isn't outrageous, as it is consistent with other data.