Sabrina -
OK, I googled too and totally take your point about the Guardian journalist. Not a massive basis for objectivity, I admit.
On money: the Leeds study mentions £232 as an average (nationwide, I presume). If that's for a 4-8 hour shift it's actually very good and much better than most casual work that doesn't require professional qualifications. Now, ANY work of that nature is going to be variable in profitability. I'm self-employed and I know exactly what that's like, earning shedloads one week and nothing the next. But I still tot everything up at the end of each month and end of each year (for the taxman), take an average and use that as a basis for my outgoings.
There's no point in dwelling on the fact that there will be some bad nights, because that's already accounted for in the average. That's what an average means, after all. If a lapdancer averages £232 per night, and there are some nights when she gets nothing, that means by definition there will be other nights when she gets £464 - or however it balances out. If the nationwide average is £232 per night and there are some lapdancers out there only averaging £100 or less, that means there must also be some earning £300 or £400 +.
Likewise, there's no point dwelling on the commission they have to pay to the club, since this is already accounted for (I presume) in the figure of their average earnings.
Is self-employment by commission a stressful way to earn your living? Sure it is. But no more stressful for a lapdancer than for a sales rep, freelance writer or plenty of other jobs, I suppose. It's a choice each person has to make, whether to stay in such a job working for fairly lucrative but uncertain returns, or take a job that is less lucrative overall but more assured. Some of that comes down to personality, some to what else the person has to consider in their life (whether they have children, a partner in a steady job etc.)
But after taking the stress of uncertainty into account, the only meaningful figure to be talking about is the average. If you're going to make a point of the minimum, then you need to equally take into account the maximum too.