In addition, monetary factors affect income distribution and economic growth. Income distribution is a nominal variable and economic growth is an actual variable. The concept of currency neutrality may apply in economic-growth research; while studying income distribution, currency factors are important and cannot be ignored. The income gap affects the achievement of the ultimate goal of the monetary policy. Economics schools such as Marx, Malthus, and Cairns all believe that the law of diminishing marginal propensity to consume lowers the consumption rate of high-income people, and the corresponding savings rate becomes higher. If the income gap is too large and wealth is too concentrated, it will affect the demand of the whole society, which, if seriously insufficient, induces an economic recession. At the same time, insufficient domestic consumption and excessive savings will also be reflected in an imbalance of the balance of payments, which will affect the monetary policy's ability to achieve its ultimate goal. If the income gap is too large, it will also reduce the liquidity of a country's social class and the resilience of economic growth in the medium- and long-term, which will have a negative impact on economic growth. These issues will affect the monetary policy's ability to achieve its ultimate goal, which should be a part of the central bank's vision.
