Basically, the idea was that a unique feature of Protestant Christianity is its emphasis on work as a duty to God. While other religions asked people to do things that were laborious and time consuming, only Protestantism (so the theory went) channelled that religious duty into productive work.
It's important to take some time out here to understand what's meant by 'work ethic'. It certainly isn't simply productivity. The richest, most productive countries actually have the lowest work ethic.
And a lack of 'work ethic' doesn't mean you're lazy or driven only by financial reward. In fact, educated people have a lower 'work ethic' than uneducated people. Clearly educated people aren't lazy - they work hard to get their qualifications and don't get paid to do it.
So 'work ethic' is actually about working for no clear purpose - it's work for work's sake.
Well, in the 100 years since there's been a lot of debate and no clear conclusion about whether Weber was right. But, in theory, it seems plausible. According to economists, people only do work if they are going to get some kind of reward. If you can convince them them that their reward will be 'magical' (some kind of spiritual reward in this life or the next) then you won't have to pay them as much.
In modern economic terms, a Protestant would gain extra 'utility' from doing work, and so they would have additional motivation to work harder.
But even if the idea did hold in the past, does it still work in the modern world? And if it does, how does it work in practice? A new paper by Hans Geser has taken a look.
He scrutinized data from the Christians in the World Values Survey and found that, as far as work ethic goes, Protestantism probably isn't very much different from Catholicism and Orthodox Christianity.
But he did find some interesting relationships with religion in general. Basically, people with stronger religious faith have a stronger work ethic. But other factors of religion - whether people took Church teaching seriously, whether they went to Church, or whether they prayed - seemed to have little or no effect.
There was a surprise, however. Belief in an afterlife actually had a negative effect on work ethic.
The effect of religion was small. Overall, only around 5% of the variation between people in work ethic is explained by religion. But Geser's analysis suggests that it's not due to religious teachings. And the promise of a reward in heaven actually has a negative effect.
Which suggests that the reason religious people have a higher work ethic is that they expect to get a reward for it in this life, rather than the next.
One last thing. The effect of religion, which is small even in poor countries, disappears in rich countries. That's not because the effects at an individual level get less. What happens is that the 'national average' intensity of religious faith has a cultural effect - increasing the work ethic of believers and non-believers.
As countries get richer, their culture shifts from a religious to a secular one. And with that, the idea of working for the sake of work becomes marginalised. In rich countries, people work because they see a reason to do the work.
Hans Geser (2009). Work Values and Christian Religiosity: An Ambiguous Multidimensional Relationship Journal of Religion and Society, 11 (24)
This work by Tom Rees is licensed under a Creative Commons Attribution-Share Alike 2.0 UK: England & Wales License.