How could one measure changes (improvements) in conditions of employment across many countries and over periods of several years? Are there any datasets readily available? And what specific indicators one could seek (assuming increase in wages would be one such obvious indicator, what else?} And is there any literature on this topic you're familiar with?
Conditions of employment are specific (particular) to any state that may, for various reasons (such as the economic crisis or political changes), modify them. The available data can be found in the information sites of citizens wishing to work in a particular state, and the specific indicators below the minimum wage are the general labor and social insurance conditions in that state. At the level of each state, even a member of the EU, there are analyzes of these aspects from the doctrinal and jurisprudential point of view, but also for informative purposes.
