changes to work.. wouldnt that be like, giving frictional unemployment, and would leave workers who were skilled, but had the wrong types of skills, so couldnt properly fill the vacant positions, requiring retraining and increasing unemployment until they changed industries and stuff
changes to the workforce.. could be like now, how we've got an ageing population, so we're lacking skilled workers to fill positions, or like in brazil were because of medical technology 50% of their population is under 17, so they have labour shortages to produce to supply all these growing kiddies etc.
obviously you'll need to extrapolate and probably come up with a lot mroe than this, but could be some areas to start your thought, stimulate a bit. OR, could be completely wrong and incorrect in everyway of what youre assessment really requires.