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Investment in New Capital. DOUBLE FEATURE. DOUBLE FEATURE. Technology and Economic Growth. The story of economic growth goes on. General framework: Y = F( L , K ,T) Previous lecture looked at L and began an analysis of K
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Investment in New Capital DOUBLE FEATURE DOUBLE FEATURE Technology and Economic Growth
The story of economic growth goes on • General framework: Y = F(L,K,T) • Previous lecture looked at Land began an analysis of K • Today we continue our discussion of capital (K) by using the model--developed last time--of the shares of spending in the whole economy • We then go on to consider technology T
Spending Allocation Model(C/Y) + (I/Y) + (X/Y) + (G/Y) = 1 • In words, sum of spending shares equals 1 • Or: (C/Y) + (I/Y) + (X/Y) = 1 - (G/Y) • LEFT HAND SIDE depends negatively on the interest rate. (Because each of C/Y, I/Y, and X/Y depends on interest rate) • Find interest rate that satisfies the equation • Then find (C/Y), (I/Y), (X/Y)
Can you draw this by hand as in an examination? • Yes, • Show all four graphs. • Focus on the (d) graph
Now consider the effects of an increase in G/Y • That is, government purchases rise as a share of GDP (like 1980s Reagan defense buildup) • “Permanent” or at least long lasting • Look at long-run effects • About 5 years, but we are not really sure how long the long run is
Now look at the graphs drawn to scale to see what happens if G/Y increases by a particular amount ?
Summary of effects of an increase in G/Y • higher interest rate • higher dollar exchange rate • (example: 160 yen per dollar rather than 120 yen per dollar) • investment lower (I/Y down) • lower net exports (X/Y down) • trade deficit rises
Key points about SAM • Applies to the long-run • The short run effects could be different • The interest rate is the real interest rate • real interest rate = interest rate minus expected rate of inflation • Can also look at other issues: • (G/Y) down, or shifts in (I/Y), (C/Y), or (X/Y) • good exam question!
Saving-investment approach • Exploits idea that by definition national saving S = Y - C - G • or (S/Y) = 1 - (C/Y) - (G/Y) • thus S/Y is positively related to the interest rate • Also (I/Y) + (X/Y) is negatively related to the interest rate • Finally S = I + X • or S/Y = I/Y + X/Y
Labor Alone: diminishing returns, subsistence, Malthusian equilibrium
But capital also has diminishing returns, so growth would not continue with capital and labor alone; need something else:technology