When the Reserve Bank Governor is saying he’d like to see stronger wage growth, you know the problem has become dire.

Over the past six years, real wages have grown at just 0.7 per cent a year. In the six years before that – a period spanning the Global Financial Crisis – real wages grew at 1.8 per cent annually. Among the likely culprits for the wages slowdown are poor productivity, declining union membership rates, wage theft scandals, penalty rate cuts, and public sector wage caps.

But another factor may also be to blame: constraints on job mobility. Standard economics tells us that wages increase when employees are in demand. If you have a dozen job offers, you’re likely to earn more than if you’re stuck with a single option. That’s part of the reason that people earn more in big cities, and less in one-company towns. Employees who switch firms tend to get a bigger pay bump than those who stay put.

Last year, Princeton economists Alan Krueger and Orley Ashenfelter uncovered a disturbing way that US firms had prevented job switching: clauses in franchise agreements that made it hard for workers to move between outlets in the same chain. Fully 58 per cent of franchise agreements, they found, contained ''no poach'' clauses, which barred franchisees from enticing workers to change stores. Among the biggest offenders were Burger King, Jiffy Lube and H&R Block.