Post on 22-Jul-2020
Why Has Inequality Been Rising? (based on work with M. Kremer)
E. Maskin
I.S.E.O. Summer School June 2017
2
• In last 30 years, significant increase in income inequality
3
• In last 30 years, significant increase in income inequality – in many rich countries (including U.S.)
4
• In last 30 years, significant increase in income inequality – in many rich countries (including U.S.) – in many poor countries (including India and
Mexico)
5
• In last 30 years, significant increase in income inequality – in many rich countries (including U.S.) – in many poor countries (including India and
Mexico) • referring here to inequality increases within
countries
6
• In last 30 years, significant increase in income inequality – in many rich countries (including U.S.) – in many poor countries (including India and
Mexico) • referring here to inequality increases within
countries – inequality has been falling across countries
7
• In last 30 years, significant increase in income inequality – in many rich countries (including U.S.) – in many poor countries (including India and
Mexico) • referring here to inequality increases within
countries – inequality has been falling across countries – many poor countries (especially India and
China) are catching up
8
• In last 30 years, significant increase in income inequality – in many rich countries (including U.S.) – in many poor countries (including India and
Mexico) • referring here to inequality increases within
countries – inequality has been falling across countries – many poor countries (especially India and
China) are catching up • Increases are theoretically puzzling
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First, take inequality increase in U.S.
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First, take inequality increase in U.S. • well accepted relationship
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First, take inequality increase in U.S. • well accepted relationship wage education/training (skill) ↔
12
First, take inequality increase in U.S. • well accepted relationship wage education/training (skill) • dispersion of skill has risen in U.S. (also the
median)
↔
13
First, take inequality increase in U.S. • well accepted relationship wage education/training (skill) • dispersion of skill has risen in U.S. (also the
median) • but not nearly so much as dispersion in income
↔
14
First, take inequality increase in U.S. • well accepted relationship wage education/training (skill) • dispersion of skill has risen in U.S. (also the
median) • but not nearly so much as dispersion in income
– holding wage as a function of skill fixed, shift in skill distribution explains only 20% of increase in income dispersion between 1980 and 2000
↔
15
First, take inequality increase in U.S. • well accepted relationship wage education/training (skill) • dispersion of skill has risen in U.S. (also the
median) • but not nearly so much as dispersion in income
– holding wage as a function of skill fixed, shift in skill distribution explains only 20% of increase in income dispersion between 1980 and 2000
– but wage schedule not fixed
↔
16
First, take inequality increase in U.S. • well accepted relationship wage education/training (skill) • dispersion of skill has risen in U.S. (also the
median) • but not nearly so much as dispersion in income
– holding wage as a function of skill fixed, shift in skill distribution explains only 20% of increase in income dispersion between 1980 and 2000
– but wage schedule not fixed • Why not?
↔
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• One popular answer: skill-biased technological change
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• One popular answer: skill-biased technological change – technology biased in favor of high skills
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• One popular answer: skill-biased technological change – technology biased in favor of high skills – marginal product of high-skill workers enhanced their wages rise relative to low-skill workers’ wages
⇒
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• One popular answer: skill-biased technological change – technology biased in favor of high skills – marginal product of high-skill workers enhanced their wages rise relative to low-skill workers’ wages
• Objection:
⇒
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• One popular answer: skill-biased technological change – technology biased in favor of high skills – marginal product of high-skill workers enhanced their wages rise relative to low-skill workers’ wages
• Objection: – difficult to measure such technological change
⇒
22
• One popular answer: skill-biased technological change – technology biased in favor of high skills – marginal product of high-skill workers enhanced their wages rise relative to low-skill workers’ wages
• Objection: – difficult to measure such technological change – rather complicated theory
⇒
23
• One popular answer: skill-biased technological change – technology biased in favor of high skills – marginal product of high-skill workers enhanced their wages rise relative to low-skill workers’ wages
• Objection: – difficult to measure such technological change – rather complicated theory
• Propose a different (simpler) theory based on matching
⇒
24
• One popular answer: skill-biased technological change – technology biased in favor of high skills – marginal product of high-skill workers enhanced their wages rise relative to low-skill workers’ wages
• Objection: – difficult to measure such technological change – rather complicated theory
• Propose a different (simpler) theory based on matching – firm matches workers of different skills to produce output
⇒
25
• One popular answer: skill-biased technological change – technology biased in favor of high skills – marginal product of high-skill workers enhanced their wages rise relative to low-skill workers’ wages
• Objection: – difficult to measure such technological change – rather complicated theory
• Propose a different (simpler) theory based on matching – firm matches workers of different skills to produce output – as skill dispersion and median increase, pattern of matching
between workers of different skills within firm changes
⇒
26
• One popular answer: skill-biased technological change – technology biased in favor of high skills – marginal product of high-skill workers enhanced their wages rise relative to low-skill workers’ wages
• Objection: – difficult to measure such technological change – rather complicated theory
• Propose a different (simpler) theory based on matching – firm matches workers of different skills to produce output – as skill dispersion and median increase, pattern of matching
between workers of different skills within firm changes – can induce even bigger increase in income dispersion
⇒
27
• One popular answer: skill-biased technological change – technology biased in favor of high skills – marginal product of high-skill workers enhanced their wages rise relative to low-skill workers’ wages
• Objection: – difficult to measure such technological change – rather complicated theory
• Propose a different (simpler) theory based on matching – firm matches workers of different skills to produce output – as skill dispersion and median increase, pattern of matching
between workers of different skills within firm changes – can induce even bigger increase in income dispersion – leads to greater relative segregation of skill within firms
⇒
28
• This last prediction is novel to our theory: variation of skills within firm falls relative to
variation across firms
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• This last prediction is novel to our theory: variation of skills within firm falls relative to
variation across firms • Illustrative examples
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• This last prediction is novel to our theory: variation of skills within firm falls relative to
variation across firms • Illustrative examples
– General Motors: typical large firm of generation ago mixed high-skill labor (engineers) with low-skill labor (assembly-line workers)
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• This last prediction is novel to our theory: variation of skills within firm falls relative to
variation across firms • Illustrative examples
– General Motors: typical large firm of generation ago mixed high-skill labor (engineers) with low-skill labor (assembly-line workers) – typical firms of today:
32
• This last prediction is novel to our theory: variation of skills within firm falls relative to
variation across firms • Illustrative examples
– General Motors: typical large firm of generation ago mixed high-skill labor (engineers) with low-skill labor (assembly-line workers) – typical firms of today: Microsoft (mainly high-skill) and
33
• This last prediction is novel to our theory: variation of skills within firm falls relative to
variation across firms • Illustrative examples
– General Motors: typical large firm of generation ago mixed high-skill labor (engineers) with low-skill labor (assembly-line workers) – typical firms of today: Microsoft (mainly high-skill) and McDonald’s (mainly low-skill)
34
• This last prediction is novel to our theory: variation of skills within firm falls relative to
variation across firms • Illustrative examples
– General Motors: typical large firm of generation ago mixed high-skill labor (engineers) with low-skill labor (assembly-line workers) – typical firms of today: Microsoft (mainly high-skill) and McDonald’s (mainly low-skill)
• segregation prediction borne out by evidence for U.S., U.K., and France
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Second, growth of inequality in Mexico
36
Second, growth of inequality in Mexico • followed a period of liberalized trade
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Second, growth of inequality in Mexico • followed a period of liberalized trade
– Mexico joined GATT in 1985
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Second, growth of inequality in Mexico • followed a period of liberalized trade
– Mexico joined GATT in 1985 – in 2 years average tariffs fell by 50%
39
Second, growth of inequality in Mexico • followed a period of liberalized trade
– Mexico joined GATT in 1985 – in 2 years average tariffs fell by 50% – FDI quadrupled
40
Second, growth of inequality in Mexico • followed a period of liberalized trade
– Mexico joined GATT in 1985 – in 2 years average tariffs fell by 50% – FDI quadrupled
• white-collar wages increased by 16%
41
Second, growth of inequality in Mexico • followed a period of liberalized trade
– Mexico joined GATT in 1985 – in 2 years average tariffs fell by 50% – FDI quadrupled
• white-collar wages increased by 16% • blue-collar wages fell by 14%
42
Second, growth of inequality in Mexico • followed a period of liberalized trade
– Mexico joined GATT in 1985 – in 2 years average tariffs fell by 50% – FDI quadrupled
• white-collar wages increased by 16% • blue-collar wages fell by 14% • globalization (increase in trade) aggravated
inequality
43
Contradicts Heckscher-Ohlin theory
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Contradicts Heckscher-Ohlin theory • Mexico has comparative advantage in low-skill labor
45
Contradicts Heckscher-Ohlin theory • Mexico has comparative advantage in low-skill labor • in autarky,
46
Contradicts Heckscher-Ohlin theory • Mexico has comparative advantage in low-skill labor • in autarky,
– high-skill labor in short supply, so commands especially high wage
47
Contradicts Heckscher-Ohlin theory • Mexico has comparative advantage in low-skill labor • in autarky,
– high-skill labor in short supply, so commands especially high wage – low-skill labor paid correspondingly poorly
48
Contradicts Heckscher-Ohlin theory • Mexico has comparative advantage in low-skill labor • in autarky,
– high-skill labor in short supply, so commands especially high wage – low-skill labor paid correspondingly poorly
• opposite true in U.S.:
49
Contradicts Heckscher-Ohlin theory • Mexico has comparative advantage in low-skill labor • in autarky,
– high-skill labor in short supply, so commands especially high wage – low-skill labor paid correspondingly poorly
• opposite true in U.S.: – high-skill labor gets comparatively low wage
50
Contradicts Heckscher-Ohlin theory • Mexico has comparative advantage in low-skill labor • in autarky,
– high-skill labor in short supply, so commands especially high wage – low-skill labor paid correspondingly poorly
• opposite true in U.S.: – high-skill labor gets comparatively low wage – low-skill labor paid comparatively well
51
Contradicts Heckscher-Ohlin theory • Mexico has comparative advantage in low-skill labor • in autarky,
– high-skill labor in short supply, so commands especially high wage – low-skill labor paid correspondingly poorly
• opposite true in U.S.: – high-skill labor gets comparatively low wage – low-skill labor paid comparatively well
• after trade opened, factor prices should equalize
52
Contradicts Heckscher-Ohlin theory • Mexico has comparative advantage in low-skill labor • in autarky,
– high-skill labor in short supply, so commands especially high wage – low-skill labor paid correspondingly poorly
• opposite true in U.S.: – high-skill labor gets comparatively low wage – low-skill labor paid comparatively well
• after trade opened, factor prices should equalize – high-skill wages in Mexico should fall
53
Contradicts Heckscher-Ohlin theory • Mexico has comparative advantage in low-skill labor • in autarky,
– high-skill labor in short supply, so commands especially high wage – low-skill labor paid correspondingly poorly
• opposite true in U.S.: – high-skill labor gets comparatively low wage – low-skill labor paid comparatively well
• after trade opened, factor prices should equalize – high-skill wages in Mexico should fall – low-skill wages in Mexico rise
54
Contradicts Heckscher-Ohlin theory • Mexico has comparative advantage in low-skill labor • in autarky,
– high-skill labor in short supply, so commands especially high wage – low-skill labor paid correspondingly poorly
• opposite true in U.S.: – high-skill labor gets comparatively low wage – low-skill labor paid comparatively well
• after trade opened, factor prices should equalize – high-skill wages in Mexico should fall – low-skill wages in Mexico rise
• trade should decrease inequality in Mexico
55
• Will argue that same matching model explains Mexico’s higher inequality
56
• Will argue that same matching model explains Mexico’s higher inequality
• But first return to inequality in U.S. (also U.K. and France)
57
• 1-good economy
58
• 1-good economy • good produced by competitive firms
59
• 1-good economy • good produced by competitive firms • labor only input
60
• 1-good economy • good produced by competitive firms • labor only input • labor comes in 3 skill levels q L < M < H
61
• 1-good economy • good produced by competitive firms • labor only input • labor comes in 3 skill levels q L < M < H • proportion of workers having skill q
( )p q =
62
All firms have same production process
63
All firms have same production process • 2 tasks
64
All firms have same production process • 2 tasks
– one “managerial” - - sensitive to skill level
65
All firms have same production process • 2 tasks
– one “managerial” - - sensitive to skill level – one “subordinate” - - less sensitive to skill output = 2
s mq q
66
All firms have same production process • 2 tasks
– one “managerial” - - sensitive to skill level – one “subordinate” - - less sensitive to skill output =
• formula incorporates 3 critical features
2s mq q
67
All firms have same production process • 2 tasks
– one “managerial” - - sensitive to skill level – one “subordinate” - - less sensitive to skill output =
• formula incorporates 3 critical features (i) workers of different skills imperfect substitutes
2s mq q
68
All firms have same production process • 2 tasks
– one “managerial” - - sensitive to skill level – one “subordinate” - - less sensitive to skill output =
• formula incorporates 3 critical features (i) workers of different skills imperfect substitutes (ii) different tasks within firm complementary
2s mq q
69
All firms have same production process • 2 tasks
– one “managerial” - - sensitive to skill level – one “subordinate” - - less sensitive to skill output =
• formula incorporates 3 critical features (i) workers of different skills imperfect substitutes (ii) different tasks within firm complementary (iii) different tasks differentially sensitive to skill
2s mq q
70
(i) workers of different skills imperfect substitutes
71
(i) workers of different skills imperfect substitutes
• if perfect substitutability, q-worker (worker of skill q) can be replaced by 2 -workers
2q
72
(i) workers of different skills imperfect substitutes
• if perfect substitutability, q-worker (worker of skill q) can be replaced by 2 -workers
• so, no prediction about skill levels in firm - - no segregation
2q
73
(i) workers of different skills imperfect substitutes
• if perfect substitutability, q-worker (worker of skill q) can be replaced by 2 -workers
• so, no prediction about skill levels in firm - - no segregation • q-worker always paid twice as much as -worker
2q
2q
74
(i) workers of different skills imperfect substitutes
• if perfect substitutability, q-worker (worker of skill q) can be replaced by 2 -workers
• so, no prediction about skill levels in firm - - no segregation • q-worker always paid twice as much as -worker
– so inequality between q-worker and -worker can’t increase
2q
2q
2q
75
(ii) different tasks complementary
76
(ii) different tasks complementary • if instead
77
(ii) different tasks complementary • if instead
( ) ( )output s mf q g q= +
78
(ii) different tasks complementary • if instead
optimal choice of independent of that of
( ) ( )output s mf q g q= +
sq mq
79
(ii) different tasks complementary • if instead
optimal choice of independent of that of • so again no prediction about combination of
skill levels in firm
( ) ( )output s mf q g q= +
sq mq
80
(iii) different tasks differentially sensitive to skill
81
(iii) different tasks differentially sensitive to skill • if instead
82
(iii) different tasks differentially sensitive to skill • if instead
output ,s mq q=
83
(iii) different tasks differentially sensitive to skill • if instead
get complete segregation of skill:
output ,s mq q=
s mq q=
84
(iii) different tasks differentially sensitive to skill • if instead
get complete segregation of skill:
– fully assortative matching
output ,s mq q=
s mq q=
85
(iii) different tasks differentially sensitive to skill • if instead
get complete segregation of skill:
– fully assortative matching • differential sensitivity
output ,s mq q=
s mq q=
2output s mq q=
86
(iii) different tasks differentially sensitive to skill • if instead
get complete segregation of skill:
– fully assortative matching • differential sensitivity
– still have some assortative matching
output ,s mq q=
s mq q=
2output s mq q=
87
(iii) different tasks differentially sensitive to skill • if instead
get complete segregation of skill:
– fully assortative matching • differential sensitivity
– still have some assortative matching – also have second force
output ,s mq q=
s mq q=
2output s mq q=
88
(iii) different tasks differentially sensitive to skill • if instead
get complete segregation of skill:
– fully assortative matching • differential sensitivity
– still have some assortative matching – also have second force
output ,s mq q=
s mq q=
implies m sq q>
2output s mq q=
89
Competitive equilibrium
90
Competitive equilibrium • wage schedule ( )w q∗
91
Competitive equilibrium • wage schedule • matching rule
( )w q∗
92
Competitive equilibrium • wage schedule • matching rule
( ), equilibrium fraction of matches with , s m
q qq q q q
π ′ =
′= =
( )w q∗
93
Competitive equilibrium • wage schedule • matching rule
( )
( )( ) ( )2
, ,, arg max , (output maximized)
q qq q q q
ππ π∗
⋅ ⋅ ′
′ ′⋅ ⋅ = ∑
( ), equilibrium fraction of matches with , s m
q qq q q q
π ′ =
′= =
( )w q∗
94
Competitive equilibrium • wage schedule • matching rule
( )
( )( ) ( )2
, ,, arg max , (output maximized)
q qq q q q
ππ π∗
⋅ ⋅ ′
′ ′⋅ ⋅ = ∑
( ), equilibrium fraction of matches with , s m
q qq q q q
π ′ =
′= =
( )w q∗
( ) ( ) ( )2 0q q w q w q∗ ∗′ ′− − ≤
95
Competitive equilibrium • wage schedule • matching rule
( )
( )( ) ( )2
, ,, arg max , (output maximized)
q qq q q q
ππ π∗
⋅ ⋅ ′
′ ′⋅ ⋅ = ∑
( ), equilibrium fraction of matches with , s m
q qq q q q
π ′ =
′= =
( )w q∗
( ) ( ) ( )2 0q q w q w q∗ ∗′ ′− − ≤
( ) equality if , 0 (no profit in equilibrium)q qπ ∗ ′− >
96
suppose
97
suppose
( ) ( ) ( ) 13p L p M p H= = =
98
suppose
claim: if low dispersion ( 2 ), thenH L<
( ) ( ) ( ) 13p L p M p H= = =
99
suppose
( ) ( ) ( ) 13, , ,L M L H M Hπ π π∗ ∗ ∗= = =
claim: if low dispersion ( 2 ), thenH L<
( ) ( ) ( ) 13p L p M p H= = =
100
suppose
•
( ) ( ) ( ) 13, , ,L M L H M Hπ π π∗ ∗ ∗= = =
claim: if low dispersion ( 2 ), thenH L<
( ) ( ) ( ) 13p L p M p H= = =
3 2 2>
101
suppose
• • so
( ) ( ) ( ) 13, , ,L M L H M Hπ π π∗ ∗ ∗= = =
claim: if low dispersion ( 2 ), thenH L<
( ) ( ) ( ) 13p L p M p H= = =
3 2 2>3 3 34 2 2 , and soL L L> +
102
suppose
• • so
( ) ( ) ( ) 13, , ,L M L H M Hπ π π∗ ∗ ∗= = =
claim: if low dispersion ( 2 ), thenH L<
( ) ( ) ( ) 13p L p M p H= = =
3 2 2>3 3 34 2 2 , and soL L L> +
2 3 3(1) 2LM L M> +
103
suppose
• • so
• if then
( ) ( ) ( ) 13, , ,L M L H M Hπ π π∗ ∗ ∗= = =
claim: if low dispersion ( 2 ), thenH L<
( ) ( ) ( ) 13p L p M p H= = =
( ), 0 ( -workers "self-matched")L L Lπ ∗ >
3 2 2>3 3 34 2 2 , and soL L L> +
2 3 3(1) 2LM L M> +
104
suppose
• • so
• if then
( ) ( ) ( ) 13, , ,L M L H M Hπ π π∗ ∗ ∗= = =
claim: if low dispersion ( 2 ), thenH L<
( ) ( ) ( ) 13p L p M p H= = =
( ), 0 ( -workers "self-matched")L L Lπ ∗ >
( ), 0 from (1)M Mπ ∗ =
3 2 2>3 3 34 2 2 , and soL L L> +
2 3 3(1) 2LM L M> +
105 105
− +
( ) 2 3 3 similarly, , 0 because 2 H H LH L Hπ ∗ = >
106 106
− + − hence,
( ) 2 3 3 similarly, , 0 because 2 H H LH L Hπ ∗ = >
( ) , 0M Hπ ∗ >
107 107
− + − hence, − but
( ) 2 3 3 similarly, , 0 because 2 H H LH L Hπ ∗ = >
( ) , 0M Hπ ∗ >2 2 3 2 , contradictionLM LH L MH+ > +
108 108
− + − hence, − but • hence,
( ) ( ) ( ) , 0; similarly , , 0L L M M H Hπ π π∗ ∗= = =
( ) 2 3 3 similarly, , 0 because 2 H H LH L Hπ ∗ = >
( ) , 0M Hπ ∗ >2 2 3 2 , contradictionLM LH L MH+ > +
109 109
− + − hence, − but • hence, • +
( ) ( ) ( ) , 0; similarly , , 0L L M M H Hπ π π∗ ∗= = =
( ) 2 3 3 similarly, , 0 because 2 H H LH L Hπ ∗ = >
( ) , 0M Hπ ∗ >2 2 3 2 , contradictionLM LH L MH+ > +
( ) ( )2 ,LM w L w M∗ ∗=
110 110
− + − hence, − but • hence, • +
( ) ( ) ( ) , 0; similarly , , 0L L M M H Hπ π π∗ ∗= = =
( ) 2 3 3 similarly, , 0 because 2 H H LH L Hπ ∗ = >
( ) , 0M Hπ ∗ >2 2 3 2 , contradictionLM LH L MH+ > +
( ) ( )2 ,LM w L w M∗ ∗=
( ) ( )2 ,LH w L w H∗ ∗= +
111 111
− + − hence, − but • hence, • +
( ) ( ) ( ) , 0; similarly , , 0L L M M H Hπ π π∗ ∗= = =
( ) 2 3 3 similarly, , 0 because 2 H H LH L Hπ ∗ = >
( ) , 0M Hπ ∗ >2 2 3 2 , contradictionLM LH L MH+ > +
( ) ( )2 ,LM w L w M∗ ∗=
( ) ( )2 ,LH w L w H∗ ∗= +
( ) ( )2MH w M w H∗ ∗= +
112
•
( )2 2 2
2LM LH MHw L∗ + −
=
113
•
( )2 2 2
2LM LH MHw L∗ + −
=
( )2 2 2
2LM MH LHw M∗ + −
=
114
•
( )2 2 2
2LM LH MHw L∗ + −
=
( )2 2 2
2LM MH LHw M∗ + −
=
( )2 2 2
2LH MH LMw H∗ + −
=
115
•
• Notice
( )2 2 2
2LM LH MHw L∗ + −
=
( )2 2 2
2LM MH LHw M∗ + −
=
( )2 2 2
2LH MH LMw H∗ + −
=
( ) ( )0 0w L w H
M M
∗ ∗∂ ∂> <
∂ ∂
116
•
• Notice Proposition 1: Starting from low skill dispersion, ,
increase in median skill reduces inequality in wages (and raises mean and median wage)
( )2 2 2
2LM LH MHw L∗ + −
=
( )2 2 2
2LM MH LHw M∗ + −
=
( )2 2 2
2LH MH LMw H∗ + −
=
( ) ( )0 0w L w H
M M
∗ ∗∂ ∂> <
∂ ∂
2 H L<
117
But opposite occurs if skill distribution dispersed
118
But opposite occurs if skill distribution dispersed – claim: this what happened in U.S., U.K., and France
119
But opposite occurs if skill distribution dispersed – claim: this what happened in U.S., U.K., and France
Proposition 2: Starting from sufficiently dispersed skill distribution
increase in median inequality:M magnifies( )34
3 2 and ,M L H M> >
120
But opposite occurs if skill distribution dispersed – claim: this what happened in U.S., U.K., and France
Proposition 2: Starting from sufficiently dispersed skill distribution
increase in median inequality:M magnifies
( ) ( )0 and 0,w L w H
M M
∗ ∗∂ ∂≤ ≥
∂ ∂
( )343 2 and ,M L H M> >
121
But opposite occurs if skill distribution dispersed – claim: this what happened in U.S., U.K., and France
Proposition 2: Starting from sufficiently dispersed skill distribution
and if either L-workers or M-workers not self-
matched, at least one equality strict
increase in median inequality:M magnifies
( ) ( )0 and 0,w L w H
M M
∗ ∗∂ ∂≤ ≥
∂ ∂
( )343 2 and ,M L H M> >
122
Proof: Suppose
( ) ( ) ( ) 315 5p L p H p M= = =
123
Proof: Suppose (2)
( ) ( ) ( ) 315 5p L p H p M= = =
2 3 3 2 3 32 2LM L M MH M H> + > +
124
Proof: Suppose (2)
•
( ) , 0 because L H H Lπ ∗ = >>
( ) ( ) ( ) 315 5p L p H p M= = =
2 3 3 2 3 32 2LM L M MH M H> + > +
125
Proof: Suppose (2)
•
•
( ) , 0 because L H H Lπ ∗ = >>
( ) ( ) ( ) 315 5p L p H p M= = =
2 3 3 2 3 32 2LM L M MH M H> + > +
* * ( , ) = ( , ) = 0 from (2)L L H Hπ π
126
Proof: Suppose (2)
•
•
•
( ) , 0 because L H H Lπ ∗ = >>
( ) ( ) ( ) 315 5p L p H p M= = =
( ) ( ) ( )2 15 5, , ,L M M H M Mπ π π∗ ∗ ∗= = =
2 3 3 2 3 32 2LM L M MH M H> + > +
* * ( , ) = ( , ) = 0 from (2)L L H Hπ π
127
Proof: Suppose (2)
•
•
•
•
( ) , 0 because L H H Lπ ∗ = >>
( ) ( ) ( ) 315 5p L p H p M= = =
( )3
(from self-matching)2
Mw M∗ =
( ) ( ) ( )2 15 5, , ,L M M H M Mπ π π∗ ∗ ∗= = =
2 3 3 2 3 32 2LM L M MH M H> + > +
* * ( , ) = ( , ) = 0 from (2)L L H Hπ π
128
Proof: Suppose (2)
•
•
•
• •
( ) , 0 because L H H Lπ ∗ = >>
( ) ( ) ( ) 315 5p L p H p M= = =
( )3
(from self-matching)2
Mw M∗ =
( ) ( ) ( )2 15 5, , ,L M M H M Mπ π π∗ ∗ ∗= = =
( ) ( )3 3
2 2,2 2
M Mw L LM w H MH∗ ∗= − = −
2 3 3 2 3 32 2LM L M MH M H> + > +
* * ( , ) = ( , ) = 0 from (2)L L H Hπ π
129
Proof: Suppose (2)
•
•
•
• •
•
( ) , 0 because L H H Lπ ∗ = >>
( ) ( ) ( ) 315 5p L p H p M= = =
( )3
(from self-matching)2
Mw M∗ =
( ) 243
32 0, since 2
w L MLM M LM
∗∂= − < >
∂
( ) ( ) ( )2 15 5, , ,L M M H M Mπ π π∗ ∗ ∗= = =
( ) ( )3 3
2 2,2 2
M Mw L LM w H MH∗ ∗= − = −
2 3 3 2 3 32 2LM L M MH M H> + > +
* * ( , ) = ( , ) = 0 from (2)L L H Hπ π
130
Proof: Suppose (2)
•
•
•
• •
•
•
( ) , 0 because L H H Lπ ∗ = >>
( ) ( ) ( ) 315 5p L p H p M= = =
( )3
(from self-matching)2
Mw M∗ =
( ) 243
32 0, since 2
w L MLM M LM
∗∂= − < >
∂
( ) ( ) ( )2 15 5, , ,L M M H M Mπ π π∗ ∗ ∗= = =
( ) ( )3 3
2 2,2 2
M Mw L LM w H MH∗ ∗= − = −
( ) 22 3
23 0, since
2w H MH H M
M
∗∂= − > >
∂
2 3 3 2 3 32 2LM L M MH M H> + > +
* * ( , ) = ( , ) = 0 from (2)L L H Hπ π
131
Segregation
132
Segregation Index of relative segregation
133
Segregation Index of relative segregation
,BB W
ρ =+
134
Segregation Index of relative segregation
B = skill variation between firms
,BB W
ρ =+
135
Segregation Index of relative segregation
B = skill variation between firms
( ) ( )2
2 - , mean skill in populationq q
q qq qµ π µ′+ ∗
′
′= =∑∑
,BB W
ρ =+
136
Segregation Index of relative segregation
B = skill variation between firms W = skill variation within firms
( ) ( )2
2 - , mean skill in populationq q
q qq qµ π µ′+ ∗
′
′= =∑∑
,BB W
ρ =+
137
Segregation Index of relative segregation
B = skill variation between firms W = skill variation within firms
( ) ( )2
2 - , mean skill in populationq q
q qq qµ π µ′+ ∗
′
′= =∑∑
,BB W
ρ =+
( ) ( )2 *2 ,q q
q qq q qπ′+
′
′= −∑∑
138
Proposition 2: Suppose
139
Proposition 2: Suppose
( ) ( ) ( ) ( ) mean skillp L p M M p H H M M+ + = =
140
Proposition 2: Suppose
If dispersion of skills big enough, i.e.,
( ) ( ) ( ) ( ) mean skillp L p M M p H H M M+ + = =
141
Proposition 2: Suppose
If dispersion of skills big enough, i.e.,
1 52
H L +
>
( ) ( ) ( ) ( ) mean skillp L p M M p H H M M+ + = =
142
Proposition 2: Suppose
If dispersion of skills big enough, i.e., then mean-preserving spread in distribution increases
segregation index
1 52
H L +
>
( ) ( ) ( ) ( ) mean skillp L p M M p H H M M+ + = =
ρ
143
Proof: Suppose
( ) ( ) ( )1 13 32, 3, 4 and 2L M H p L p H p Mε ε= = = = = + = −
144
Proof: Suppose
•
2 3 2 3Then 2 2MH L LM H+ > +
( ) ( ) ( )1 13 32, 3, 4 and 2L M H p L p H p Mε ε= = = = = + = −
145
Proof: Suppose
• • So
2 3 2 3Then 2 2MH L LM H+ > +
( ) ( ) ( )1 13 32, 3, 4 and 2L M H p L p H p Mε ε= = = = = + = −
( ) 1 16 2,L Lπ ε∗ = +
146
Proof: Suppose
• • So
2 3 2 3Then 2 2MH L LM H+ > +
( ) ( ) ( )1 13 32, 3, 4 and 2L M H p L p H p Mε ε= = = = = + = −
( ) 13, 2M Hπ ε∗ = −
( ) 1 16 2,L Lπ ε∗ = +
147
Proof: Suppose
• • So
2 3 2 3Then 2 2MH L LM H+ > +
( ) ( ) ( )1 13 32, 3, 4 and 2L M H p L p H p Mε ε= = = = = + = −
( ) 13, 2M Hπ ε∗ = −
( ), 3H Hπ ε∗ =
( ) 1 16 2,L Lπ ε∗ = +
148
Proof: Suppose
• • So
• B =
2 3 2 3Then 2 2MH L LM H+ > +
( ) ( ) ( )1 13 32, 3, 4 and 2L M H p L p H p Mε ε= = = = = + = −
( ) ( ) ( )2 2 2
1 1 16 2 3 2 3
2 2 2L L M H H HM M Mε ε ε+ + + − + + − − + −
( ) 13, 2M Hπ ε∗ = −
( ), 3H Hπ ε∗ =
( ) 1 16 2,L Lπ ε∗ = +
149
Proof: Suppose
• • So
• B =
• W =
2 3 2 3Then 2 2MH L LM H+ > +
( ) ( ) ( )1 13 32, 3, 4 and 2L M H p L p H p Mε ε= = = = = + = −
( ) ( ) ( ) ( )2 2 2 2
1 1 1 16 2 3 3
1 12 2 32 2 2 2 2 2
L L M H M H H HL M H Hε ε ε ε+ + + + − + + − − + − − + −
( ) ( ) ( )2 2 2
1 1 16 2 3 2 3
2 2 2L L M H H HM M Mε ε ε+ + + − + + − − + −
( ) 13, 2M Hπ ε∗ = −
( ), 3H Hπ ε∗ =
( ) 1 16 2,L Lπ ε∗ = +
150
Proof: Suppose
• • So
• B =
• W =
• B increasing in
2 3 2 3Then 2 2MH L LM H+ > +
( ) ( ) ( )1 13 32, 3, 4 and 2L M H p L p H p Mε ε= = = = = + = −
( ) ( ) ( ) ( )2 2 2 2
1 1 1 16 2 3 3
1 12 2 32 2 2 2 2 2
L L M H M H H HL M H Hε ε ε ε+ + + + − + + − − + − − + −
( ) ( ) ( )2 2 2
1 1 16 2 3 2 3
2 2 2L L M H H HM M Mε ε ε+ + + − + + − − + −
ε
( ) 13, 2M Hπ ε∗ = −
( ), 3H Hπ ε∗ =
( ) 1 16 2,L Lπ ε∗ = +
151
Proof: Suppose
• • So
• B =
• W =
• B increasing in
• W decreasing in
2 3 2 3Then 2 2MH L LM H+ > +
( ) ( ) ( )1 13 32, 3, 4 and 2L M H p L p H p Mε ε= = = = = + = −
( ) ( ) ( ) ( )2 2 2 2
1 1 1 16 2 3 3
1 12 2 32 2 2 2 2 2
L L M H M H H HL M H Hε ε ε ε+ + + + − + + − − + − − + −
ε
( ) ( ) ( )2 2 2
1 1 16 2 3 2 3
2 2 2L L M H H HM M Mε ε ε+ + + − + + − − + −
ε
( ) 13, 2M Hπ ε∗ = −
( ), 3H Hπ ε∗ =
( ) 1 16 2,L Lπ ε∗ = +
152
Proof: Suppose
• • So
• B =
• W =
• B increasing in
• W decreasing in
• So
2 3 2 3Then 2 2MH L LM H+ > +
( ) ( ) ( )1 13 32, 3, 4 and 2L M H p L p H p Mε ε= = = = = + = −
( ) ( ) ( ) ( )2 2 2 2
1 1 1 16 2 3 3
1 12 2 32 2 2 2 2 2
L L M H M H H HL M H Hε ε ε ε+ + + + − + + − − + − − + −
ε
( ) ( ) ( )2 2 2
1 1 16 2 3 2 3
2 2 2L L M H H HM M Mε ε ε+ + + − + + − − + −
ε
increasing in BB W
ε+
( ) 13, 2M Hπ ε∗ = −
( ), 3H Hπ ε∗ =
( ) 1 16 2,L Lπ ε∗ = +
153
Proof: Suppose
• • So
• B =
• W =
• B increasing in
• W decreasing in
• So • intuitively, B rises as weight in tails increases
2 3 2 3Then 2 2MH L LM H+ > +
( ) ( ) ( )1 13 32, 3, 4 and 2L M H p L p H p Mε ε= = = = = + = −
( ) ( ) ( ) ( )2 2 2 2
1 1 1 16 2 3 3
1 12 2 32 2 2 2 2 2
L L M H M H H HL M H Hε ε ε ε+ + + + − + + − − + − − + −
ε
( ) ( ) ( )2 2 2
1 1 16 2 3 2 3
2 2 2L L M H H HM M Mε ε ε+ + + − + + − − + −
ε
increasing in BB W
ε+
( ) 13, 2M Hπ ε∗ = −
( ), 3H Hπ ε∗ =
( ) 1 16 2,L Lπ ε∗ = +
154
Return to globalization and Mexico
155
Return to globalization and Mexico Puzzles:
156
Return to globalization and Mexico Puzzles: • Mexico has comparative advantage in low-skill labor
157
Return to globalization and Mexico Puzzles: • Mexico has comparative advantage in low-skill labor but
158
Return to globalization and Mexico Puzzles: • Mexico has comparative advantage in low-skill labor but trade increased gap between high- and low-skill workers
159
Return to globalization and Mexico Puzzles: • Mexico has comparative advantage in low-skill labor but trade increased gap between high- and low-skill workers
– contradicts Heckscher-Ohlin theory
160
Return to globalization and Mexico Puzzles: • Mexico has comparative advantage in low-skill labor but trade increased gap between high- and low-skill workers
– contradicts Heckscher-Ohlin theory • H-O implies that as 2 countries become more different (in factor endowments),
should trade more
161
Return to globalization and Mexico Puzzles: • Mexico has comparative advantage in low-skill labor but trade increased gap between high- and low-skill workers
– contradicts Heckscher-Ohlin theory • H-O implies that as 2 countries become more different (in factor endowments),
should trade more – hence, U.S. and Malawi should trade more than U.S. and Mexico (Malawi more different than Mexico from U.S.)
162
Return to globalization and Mexico Puzzles: • Mexico has comparative advantage in low-skill labor but trade increased gap between high- and low-skill workers
– contradicts Heckscher-Ohlin theory • H-O implies that as 2 countries become more different (in factor endowments),
should trade more – hence, U.S. and Malawi should trade more than U.S. and Mexico (Malawi more different than Mexico from U.S.) – but Mexico trades much more than Malawi with U.S.
163
Resolution:
164
Resolution: • think of globalization as increase in
international production
165
Resolution: • think of globalization as increase in
international production – Delhi call centers (outsourcing)
166
Resolution: • think of globalization as increase in
international production – Delhi call centers (outsourcing) – computers
167
Resolution: • think of globalization as increase in
international production – Delhi call centers (outsourcing) – computers
designed in U.S.
168
Resolution: • think of globalization as increase in
international production – Delhi call centers (outsourcing) – computers
designed in U.S. programmed in Europe
169
Resolution: • think of globalization as increase in
international production – Delhi call centers (outsourcing) – computers
designed in U.S. programmed in Europe assembled in China
170
Resolution: • think of globalization as increase in
international production – Delhi call centers (outsourcing) – computers
designed in U.S. programmed in Europe assembled in China
• due to lower communication/transport costs
171
• 2 countries – one rich, one poor
172
• 2 countries – one rich, one poor – rich country
173
• 2 countries – one rich, one poor – rich country
– workers of skill levels A and B
174
• 2 countries – one rich, one poor – rich country
– workers of skill levels A and B
– poor country
175
• 2 countries – one rich, one poor – rich country
– workers of skill levels A and B
– poor country – workers of skill levels C and D
176
• 2 countries – one rich, one poor – rich country
– workers of skill levels A and B
– poor country – workers of skill levels C and D
A B C D> > >
177
• 2 countries – one rich, one poor – rich country
– workers of skill levels A and B
– poor country – workers of skill levels C and D
A B C D> > >(conclusions still hold if )C B>
178
• 2 countries – one rich, one poor – rich country
– workers of skill levels A and B
– poor country – workers of skill levels C and D
• production
A B C D> > >(conclusions still hold if )C B>
2output s mq q=
179
• 2 countries – one rich, one poor – rich country
– workers of skill levels A and B
– poor country – workers of skill levels C and D
• production • before globalization (i.e., in autarky), workers can
match only domestically
A B C D> > >(conclusions still hold if )C B>
2output s mq q=
180
• 2 countries – one rich, one poor – rich country
– workers of skill levels A and B
– poor country – workers of skill levels C and D
• production • before globalization (i.e., in autarky), workers can
match only domestically • after globalization, international matching possible
A B C D> > >(conclusions still hold if )C B>
2output s mq q=
181
countrypoor
countryrich
DCBA >>>
182
Proposition 3: If D-workers have sufficiently low skill, i.e.,
countrypoor
countryrich
DCBA >>>
183
Proposition 3: If D-workers have sufficiently low skill, i.e.,
(*)
countrypoor
countryrich
DCBA >>>
1 5 ,2
B D +
>
184
Proposition 3: If D-workers have sufficiently low skill, i.e.,
(*) then globalization increases inequality in poor
country
countrypoor
countryrich
DCBA >>>
1 5 ,2
B D +
>
185
Proof: 2 cases
1 5(*) 2
B D +
>
rich poor country country
A B C D> > >
186
Proof: 2 cases
Case I
1 5(*) 2
B D +
>
rich poor country country
A B C D> > >
( ) ( )p D p C>
187
Proof: 2 cases
Case I •
1 5(*) 2
B D +
>
rich poor country country
A B C D> > >
( ) ( )p D p C>
( ), 0,a D Dπ ∗ >
188
Proof: 2 cases
Case I •
•
1 5(*) 2
B D +
>
rich poor country country
A B C D> > >
( ), 0 (because, from (*), -worker can't match with - or -worker)g D D D A Bπ ∗ >
( ) ( )3
2a gDw D w D∗ ∗= =
( ) ( )p D p C>
( ), 0,a D Dπ ∗ >
autarky post-globalizationa g= =
189
Proof: 2 cases
Case I •
•
•
1 5(*) 2
B D +
>
rich poor country country
A B C D> > >
( ), 0 (because, from (*), -worker can't match with - or -worker)g D D D A Bπ ∗ >
( ) ( )3
2a gDw D w D∗ ∗= =
( ) ( )p D p C>
( ), 0,a D Dπ ∗ >
( ) ( ) because of possible matching with or g aw C w C B A∗ ∗≥
autarky post-globalizationa g= =
190
Proof: 2 cases
Case I •
•
•
• Hence,
1 5(*) 2
B D +
>
rich poor country country
A B C D> > >
( ), 0 (because, from (*), -worker can't match with - or -worker)g D D D A Bπ ∗ >
( ) ( )3
2a gDw D w D∗ ∗= =
( ) ( ) ( ) ( ) - - globalization causes rise in inequalityg g a aw C w D w C w D∗ ∗ ∗ ∗− ≥ −
( ) ( )p D p C>
( ), 0,a D Dπ ∗ >
( ) ( ) because of possible matching with or g aw C w C B A∗ ∗≥
autarky post-globalizationa g= =
191
Case II
( ) ( )p D p C<
rich poor
A B C D> > >
192
Case II •
( ) ( )3
2max ,2a a
Dw D DC w C∗ ∗ ⇒ = −
( ) ( )p D p C<
( ) ( )3
, 02a a
CC C w Cπ ∗ ∗> ⇒ =
rich poor
A B C D> > >
193
Case II •
•
( ) ( ) - - at worst -workers can self-match g aw C w C C∗ ∗≥
( ) ( )3
2max ,2a a
Dw D DC w C∗ ∗ ⇒ = −
( ) ( )p D p C<
( ) ( )3
, 02a a
CC C w Cπ ∗ ∗> ⇒ =
rich poor
A B C D> > >
194
Case II •
•
•
( ) ( ) - - at worst -workers can self-match g aw C w C C∗ ∗≥
( ) ( )3
2max ,2a a
Dw D DC w C∗ ∗ ⇒ = −
( ) ( ) ( )3 3 3
2 2max , max ,2 2 2g g a
D D Cw D DC w C w D DC∗ ∗ ∗ = − ≤ = −
( ) ( )p D p C<
( ) ( )3
, 02a a
CC C w Cπ ∗ ∗> ⇒ =
rich poor
A B C D> > >
195
Case II •
•
•
• Hence, again
( ) ( ) - - at worst -workers can self-match g aw C w C C∗ ∗≥
( ) ( )3
2max ,2a a
Dw D DC w C∗ ∗ ⇒ = −
( ) ( ) ( )3 3 3
2 2max , max ,2 2 2g g a
D D Cw D DC w C w D DC∗ ∗ ∗ = − ≤ = −
( ) ( )p D p C<
( ) ( )3
, 02a a
CC C w Cπ ∗ ∗> ⇒ =
( ) ( ) rises with globalizationw C w D∗ ∗−
rich poor
A B C D> > >
196
Model also explains Malawi:
197
Model also explains Malawi: • workers in Malawi have very low skills no international matching opportunities
⇒
198
Policy?
199
Policy? • How can D-workers benefit from globalization?
200
Policy? • How can D-workers benefit from globalization? • Suppose can increase q by at cost q∆ ( )c q∆
201
Policy? • How can D-workers benefit from globalization? • Suppose can increase q by at cost
– may give D better matching opportunities q∆ ( )c q∆
202
Policy? • How can D-workers benefit from globalization? • Suppose can increase q by at cost
– may give D better matching opportunities • who will bear cost?
q∆ ( )c q∆
203
Policy? • How can D-workers benefit from globalization? • Suppose can increase q by at cost
– may give D better matching opportunities • who will bear cost?
– not firm - - education raises worker’s productivity, but then have to pay higher wage
q∆ ( )c q∆
204
Policy? • How can D-workers benefit from globalization? • Suppose can increase q by at cost
– may give D better matching opportunities • who will bear cost?
– not firm - - education raises worker’s productivity, but then have to pay higher wage – not worker perhaps can’t afford to pay
q∆ ( )c q∆
205
Policy? • How can D-workers benefit from globalization? • Suppose can increase q by at cost
– may give D better matching opportunities • who will bear cost?
– not firm - - education raises worker’s productivity, but then have to pay higher wage – not worker perhaps can’t afford to pay – role for investment by third parties domestic government international agencies, NGOs foreign aid private foundations
q∆ ( )c q∆