It thus permits identifying “gainers” and “losers” of policy reforms. The advantage of the simulation is that it can hold “everything else” constant (unemployment levels, market-income inequality, household composition, etc.), For instance, it can show whether families at the bottom, middle and top of the income distribution are now better or worse off than they would have been with unchanged policies. This leads to “automatic” changes in redistribution mechanisms, if no policy action is taken (OECD, 2008b).