ΔY/Y = ΔA/A + α(ΔK/K) + (1 – α)(ΔL/L)
ΔY/Y = Growth in gross domestic product, GDP
ΔA/A = Growth in total factor productivity = 1/5%
ΔK/K = Growth rate of capital = 3.2%
ΔL/L = Growth rate of labor = 0.4%
α = Output elasticity of capital = 0.3
1 – α = Output elasticity of labor = 0.7
The portfolio balance channel assumes that current account imbalances shift financial wealth from deficit nations to surplus nations. Countries with trade deficits will finance their trade with increased borrowing. This behavior may lead to shifts in global asset preferences, which in turn could influence the path of exchange rates.
The flow supply/demand channel mechanism focuses on the fact that purchases and sales of internationally traded goods and services require the exchange of domestic and foreign currencies in order to arrange payment for those goods and services. Such shifts in currency demand should exert upward pressure on the value of the surplus nation’s currency and downward pressure on the value of the deficit nation’s currency.
the debt sustainability channel as a means to assess the long-run equilibrium value of exchange rates. According to this mechanism, there should be some upper limit on the ability of countries to run persistently large current account deficits. If a country runs a large and persistent current account deficit over time, eventually it will experience an untenable rise in debt owed to foreign investors. If such investors believe that the deficit country’s external debt is rising to unsustainable levels, they are likely to reason that a major depreciation of the deficit country’s currency will be required at some point to ensure that the current account deficit narrows significantly and that the external debt stabilizes at a level deemed sustainable.
外部性とは、生産活動や消費活動が、特定の取引や活動、意思決定に直接関与していない他者に波及する効果のことである。
The Cobb–Douglas function exhibits constant returns to scale, which means that if all inputs are increased at the same percentage, then output rises at that percentage. Diminishing marginal productivity exists with respect to each individual input (if the other input is held constant). Continued growth in per capita output is possible even in the steady state as long as there is ongoing technological progress (increases in TFP).
