[4ii] Introducing technological progress and human capital to Long Run Growth Flashcards
4 Real Life Examples of Tech Progress?
U.S. farm sector productivity nearly tripled from 1950 to 2009.
The real price of computer power has fallen an average of 30% per year over the past three decades.
2000: 361 million Internet users, 740 million cell phone users -> 2011: 2.4 billion Internet users, 5.9 billion cell phone users
2001: iPod capacity = 5gb, 1000 songs. Not capable of playing episodes of popular TV shows. ->
2012: iPod touch capacity = 64gb, 16,000 songs. Can play episodes of popular TV shows.
What new variable do we add to the Solow model?
A new variable: E = labour efficiency
Assume: Technological progress is labour-augmenting: it increases labour efficiency at the exogenous rate g:
g = change in E / E
How is the production function written with new Variable ?
Y = F (K, L x E)
L x E = the number of effective workers
Hence, increases in labour efficiency have the same effect on output as increases in the labour force.
Notation:
y = Y/LE =
k = K/LE =
Production function per effective worker:
Saving and investment per effective worker:
Notation:
y = Y/LE = output per effective worker
k = K/LE = capital per effective worker
Production function per effective worker: y = f(k)
Saving and investment per effective worker: s y = s f(k)
Note: no longer in merely “per worker” terms.
How do you write break investment 4 variables?
How can we define break-even investment
Explain what each variable represents?
( d + n + g)k = break-even investment: the amount of investment necessary to keep k constant.
[note: δ = d]
Consists of: d k to replace depreciating capital n k to provide capital for new workers g k to provide capital for the new “effective” workers created by technological progress
3 Main Differences Between Solow Growth model with and without Tech progress
Main difference is that in the steady state, income per worker/capita is growing at rate g instead of being constant.
With tech, k and y are in “per effective worker” units rather than “per worker” units.
The break-even investment line is a little bit steeper: at any given value of k, more investment is needed to keep k from falling - in particular, gk is needed. Otherwise, technological progress will cause k = K/LE to fall at rate g (because E in the denominator is growing at rate g).
Steady-state growth rates in the Solow Model with tech. progress:
Capital per effective worker?
Output per worker?
Output per Effective worker?
Total Output?
k is constant (has zero growth rate) by definition of the steady state
Output per worker (Y/L) grows at rate g
y is constant because y = f(k) and k is constant
Y grows at rate g + n.
Why does Output per worker (Y/L) grow at rate g?
To see why Y/L grows at rate g, note that the definition of y implies (Y/L) = yE. The growth rate of (Y/L) equals the growth rate of y plus that of E. In the steady state, y is constant while E grows at rate g.
Why does Y grow at rate g + n.?
Note that Y = yEL = (yE) x L.
The growth rate of Y equals the growth rate of (yE) plus that of L. We just saw that, in the steady state, the growth rate of (yE) equals g. And we assume that L grows at rate n (no. of new workers)
What is the golden rule capital stock with tech prog?
what does MPK equal when c* is maximised?
c* = y* - i*
= f (k* ) - ( d + n + g) k*
[investment in steady state, i* =break-even investment]
c* is maximized when MPK = d + n + g
or MPK - d = n + g
In the Golden Rule Steady State, the marginal product of capital net of depreciation equals the pop. growth rate plus the rate of tech progress.
Growth empirics: Balanced growth
What does K/L grow at the same rate as?
and therefore what does this mean should be constant?
Is this true irl?
What does Y/L grow at same rate as?
and therefore what does this mean should be constant?
Is this true irl?
Solow model predicts Y/L and K/L grow at the same rate (g), so K/Y should be constant.
This is true in the real world.
Solow model predicts real wage grows at same rate as Y/L, while real rental price is constant.
Also true in the real world.
What does Solow model predict for poor countries?
why does this not mean the solow model fails?
Solow model predicts that, ceteris paribus, poor countries (with lower Y/L and K/L) should grow faster than rich ones.
If true, then the income gap between rich & poor countries would shrink over time, causing living standards to converge. In real world, many poor countries do NOT grow faster than rich ones.
No, because “other things” aren’t equal:
In samples of countries with similar savings & pop. growth rates, income gaps shrink about 2% per year.
In larger samples, after controlling for differences in saving, pop. growth, and human capital, incomes converge by about 2% per year.
What the Solow model really predicts is ____ convergence — countries converge to their own steady states, which are determined by ___, ___ growth, and e____
What the Solow model really predicts is conditional convergence—countries converge to their own steady states, which are determined by saving, population growth, and education
Two reasons why income per capita are lower in some countries than others:
does one reason influence the other explain?
Differences in capital (physical or human) per worker
Differences in the efficiency of production (the height of the production function)
[note: countries with higher capital (physical or human) per worker also tend to have higher production efficiency]
Explain why Countries with higher production efficiency also tend to have higher physical or human capital per worker ? 3 stage analysis
Production efficiency encourages capital accumulation
Capital accumulation has externalities that raise efficiency
A third, unknown variable causes cap accumulation and efficiency to be higher in some countries than