a. We measure the long-term economic growth of a country by the change of percentage rate in the GDP. The key determinants of long-run economic growth are elements of productivity, labor force participation, and demographic changes. Elements of productivity is the ratio of economic outputs to inputs, the labor force participation is the amount of workers available, and demographic changes are the influence of economic growth by the employment to population ratio.

b. The relationship between economic growth and productivity is that there has to be increased productivity or some sort of productivity in order for economic growth to happen. There also has to be materials and resources available for the productivity to increase or even maintain. That is a major source of growth in labor productivity. Investment is also a major source of growth in labor productivity, but it kind of goes hand in hand with the resources that are available to be invested in labor productivity.