Economic growth is increase in total output in the short run and increase in productive capacity in the long run. One of the objectives of governments is to have sustainable economic growth that is the growth which can continue over time. Sustainable growth helps to achieve trend growth that is expected increase in the output over time. There are many causes of economic growth in the short run and long run. Economic growth in the short run means that there is an increase in AD because of increases in components of it. For example, if there is a fall in the exchange rates, exports will be cheaper and more competitive and so the economy will have export-led growth. Or if government increased its spending on subsidies for firms, this means that prices might go down and consumption will increase. This leads to economic growth. In order to stimulate it government might use monetary or fiscal policies such as reduce interest rates or lower exchange rates, or reduce taxes, etc. In order to achieve long run economic growth government has to spend a big amount of money for supply side policies such as education or training, promoting new firms, because increase in productive capacity can be achieved through the increase in quality and quantity of labour, resources and improvements in capital goods.