His point is that a phrase like "this [teacher|nurse|officer] only makes xx" can be deceiving when the local economic context is not taken into account. Cost of

His point is that a phrase like "this [teacher|nurse|officer] only makes xx" can be deceiving when the local economic context is not taken into account. Cost of living is not equal. To give an analogue example : the same mechanism applies, in an exacerbated way, across countries. Comparing salaries of Americans with those of -for example- a Frenchman will not take into account that healthcare and education are much more expensive in the US.