This piece from the Economist covers some of the same points I’ve been making about work intensity (here and here. The summary is that the UK and France have approximately equal GDP per person. French output per hour is 20 per cent higher than British, but this is cancelled out by higher British employment rates and higher average hours per person.
I’ve argued in the past, that improvements in GDP achieved by longer hours and greater work intensity are largely illusory and the Economist largely goes along with this. On the other hand, higher employment rates are generally a positive way to achieve higher output, at least if the alternative is unemployment, rather than, for example, participation in full-time education.
A very similar analysis applies to the US, except that US productivity is about equal to that in France and other European countries, so higher employment rates and longer hours translate into higher GDP per person.
A final point is that the greater inequality in the US and the UK imply that the average (median) person falls further short of average (mean) income than in Europe.
John Quiggin 
But as the Economist asks in thr article to you link to:
“Are other Europeans better off with their greater leisure? Not necessarily. Only if they can choose between work and fun. ãIn most European countries people don’t have that choice because of restrictive labour markets and high taxes on employment,ä says Bart van Ark, professor of economics at Groningen University.”
I alluded to this point in the post. Involuntary leisure, that is, unemployment, is not a positive.
OTOH, I don’t think the kind of labour market flexibility that ‘allows’ workers in the English-speaking countries to put in lots of unpaid overtime is beneficial at all.
Some random thoughts in no particular order:
-Higher employment means more low quality workers get employed at the margin, which would reduce average productivity.
-Highly (i.e. expensively) trained workers would tend to work longer hours to maximise the return on the investment in their training.
-The article attributes lower English productivity to lower capital per employee. Is this due to poorer English management (class system leading to inbred incompetents being employed as mangers? that’s what one of my English expat colleagues thinks) or due to the fact that lower quality workers are less able to realise a better return on capital, or maybe something else?
-Are the statistics in the article accurate? Is like being compared with like here? Are black market/moonlighting/extra hours being counted in a consistent manner between countries? You know how invalid unemployment rate comparisons can be, and a 20% difference in productivity is quite something given French conditions.
-Working longer hours, even without pay, isn’t always a negative. It’s way of showing your commitment, which is in turn rewarded with better, more interesting work, more perks, opportunities for promotion, less stress as deadlines approach, greater flexibility on other working conditions like arrival time/time off/lunch breaks/dress/location etc. Also mastery is a major contributor to human happiness, and by having greater mastery over your work (perhaps as a result of more hours) can actually increase well-being overall, as well as employability. Finally, home life is not always the unbridled joy that love songs would have you believe.
-Overtime is cost effective because the firm does not have to pay additional fixed costs per employee like super/rec leave/property rental/training. Mind you, this appears to contradict the higher capital per worker in France, which makes me wonder again about the statistics.
-As Jason soon pointed out in one of your earlier threads, not all tasks are divisible – this is famously true of software writing, or other tasks with numerous, complex interfaces.
Each and every point Clem makes is a fair one. And I can think of couple more effects to add. The bottom line is that drawing conclusions about relative levels of human welfare by comparing productivity and/or working hours is fraught with traps for young players, so much so that arguments about who is on average better off between the Brits or Yanks and the continentals are unlikely to be resolved.
One lesson for Australians to bear in mind though. To the extent that increasing inequality of weekly earnings is a result of people being better able to choose their preferred earnings/leisure tradeoff (both in a static sense and in an intertemporal framework) it is a good thing, not a problem. Whether in fact this effect is a main driver of the rising inequality is an empiric question, but one that no-one seems to have tackled in a systematic way (there’s another PhD thesis in there somewhere).