economic essay
SESSION 7 25TH JANUARY 20
INTRODUCTION TO
ECONOMIC GROWTH
SOMASRI MUKHOPADHYAY
• Model in terms of Mathematics/Statistics • Model in the context of this course in Economics
Solow Model: The Basic Question
Solving the Model
Mathematical Model Finding the Values
of the Variables
In the Present Context of ECON333
We try to find out the Factors behind Growth
The Three Basic Equations • Y= f(L,K) • dK/dt = sY - ΩK
Model • Set of Equations
Describing Relationship Among “Endogenous” Variables
• Endogenous Vis-à-vis • Parameters and • Exogenous Variable
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Canada France United Kingdom Japan Korea, Rep. United States World Singapore Hong Kong SAR, China
Select Economies During 1960s
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1960 1961 1962 1963 1964 1965 1966 1967 1968 1969
G D
P P
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ap ita
a t C
ur re
nt U
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Axis Title
Chart Title
Canada France United Kingdom Japan Korea, Rep. United States World Singapore Hong Kong SAR, China
Select Economies During 1960s
0
1000
2000
3000
4000
5000
6000
Canada France United Kingdom
Japan Korea, Rep. United States
World Singapore Hong Kong SAR, China
G D
P P
er C
ap ita
a t C
ur re
nt U
D S
Axis Title
Chart Title
1960 1961 1962 1963 1964 1965 1966 1967 1968 1969
Select Economies During 1960s
Solow Model : Understanding the Equations
• The Production Function � Y = f(L,K)
= kα L1-α
� Cobb-douglas Production Function Exhibiting constant Returns to Scale
• Assumptions � Large Number of firms in the Economy
�Perfect Competition Prevails �Firms are Price Takers
� Profit Maximisation Problem for the Frim is as under � Y = kα L1-α - wL-rK
�w = Wage paid per unit of labour �r = Rent paid per unit of capital �Price of output normalised to unity.
• Profit Maximisation Requires � MPL = w � MPK = r
�Firms will employ Labour and Capital to the level where the respective per unit contribution to output equals their remuneration
� Also, � w = (1-α) Y/L � r = α (Y/K)
� And, thus, � (wL)/Y = (1-α) � (rK)/Y = α
Solow Model : Understanding the Equations
• The Factor Shares are Constant over time
• Fact 5 of chapter 1
• Y = kα L1-α • Y/L = (kα L1-α ) / L • y = kα
• y = Y/L • k = K/L
• Rewriting the Production Function in terms of Output Per worker – as we are interested in knowing the factors affecting output per capita
Solow Model : Understanding the Equations
There is Enormous Variation in Per-Capita Income across Economies
Rates of Economic Growth Vary substantially Across Countries
Growth Rates are not Generally constant over time.
A country’s Relative Position in the World distribution of Per Capita Incomes is not immutable
USA Data …….
Growth in “output” and growth in International Trade are closely related
Solow Model : Understanding the Equations
y y = Kα
k
Output per worker = Y/L= y Capital per worker = K/L = k
• Per-capita Output As A Function Of Capital Labour Ratio
• With More Capital Per Worker Firms Produce More Output Per Worker
• Capital Accumulation is the addition of Capital during a period over and above the previous period. �K (t+1) – K (t)
�dK/dt = sY - ΩK • Thus …. Not Equal to the Gross Savings of an economy
during one particular period • Rewriting the Capital Accumulation Equation to suit our
need of analysing per capita growth…… �(1/y)dy/dt = α (1/k)dk/dt
Solow Model : Understanding the Equations
• Assumption: Labour force Participation Rate is Constant ¾ If Population Grows at the rate n, labour force participation
will also grow at the rate n. ¾ (1/L)dL/dt = n
• Assumption: n = .01 ¾ Population and thus labour force grows annually by 1 per
cent. ¾ Labour grows at an exponential rate n
¾L(t) = L0ent
¾(1/L)dL/dt = n
Solow Model : Understanding the Equations Refer Back – Capital was not the only factor……..
• Assumption: Labour force Participation Rate is Constant ¾ If Population Grows at the rate n, labour force participation
will also grow at the rate n. ¾ (1/L)dL/dt = n
• Assumption: n = .01 ¾ Population and thus labour force grows annually by 1 per
cent. ¾ Labour grows at an exponential rate n
¾L(t) = L0ent
¾(1/L)dL/dt = n
Solow Model : Understanding the Equations Refer Back – Capital was not the only factor……..
• dk/dt = sy – (Ω + n)k
Solow Model : Understanding the Equations
• Increase in Population by n • Depreciation of Capital by Ω Erodes away the Capita Per worker, which is technically the Capital Labour Ratio
• Obtaining Values of the Endogenous Variables with given values of Parameters and Exogenous Variables
• The two Basic Equations of solow Model are – y = (k)α
– dK/dt = sy – (n+Ω)K
Solving the Solow Model
The Basic Solow Diagram
Introduction to Economic Growth, 3rd Edition Copyright © 2013, W.W. Norton & Company
Introduction to Economic Growth, 3rd Edition Copyright © 2013, W.W. Norton & Company
The Basic Solow Diagram Solow Diagram with the Production Function