The report’s authors wanted to know what drove nurses and doctors to join agencies, presuming it was simply a case of higher pay. But the researchers found that agency workers in the NHS had similar pay. What they found interesting was that agency workers felt better off because they had escaped the internal politics, the bureaucracy and the stricture of rotas that rarely matched the demands of home. As agency workers they believed they had more control over their lives and put up with less bullying from their employer.
A report by the National Institute for Economic & Social Research (NIESR) quoted here.