• Nie Znaleziono Wyników

2010 W. W. Norton & Company, Inc.

N/A
N/A
Protected

Academic year: 2022

Share "2010 W. W. Norton & Company, Inc."

Copied!
127
0
0

Pełen tekst

(1)

Technology Technology

© 2010 W. W. Norton & Company, Inc.

(2)

Technologies Technologies

A technology is a process by which inputs are converted to an output.

inputs are converted to an output.

E.g. labor, a computer, a projector,

E.g. labor, a computer, a projector, electricity, and software are being combined to produce this lecture.

© 2010 W. W. Norton & Company, Inc. 2

(3)

Technologies Technologies

Usually several technologies will produce the same product -- a

produce the same product -- a

blackboard and chalk can be used blackboard and chalk can be used instead of a computer and a

projector.

projector.

Which technology is “best”?

Which technology is “best”?

How do we compare technologies?

How do we compare technologies?

© 2010 W. W. Norton & Company, Inc. 3

(4)

Input Bundles Input Bundles

xi denotes the amount used of input i;

i.e. the level of input i.

i

i.e. the level of input i.

An input bundle is a vector of the

An input bundle is a vector of the input levels; (x11, x22, … , xnn).

E.g. (x1, x2, x3) = (6, 0, 9××××3).

© 2010 W. W. Norton & Company, Inc. 4

(5)

Production Functions Production Functions

y denotes the output level.

The technology’s production

function states the maximum amount function states the maximum amount of output possible from an input

bundle.

y ==== f x ( , L , x ) y ==== f x ( 1 , L , x n )

© 2010 W. W. Norton & Company, Inc. 5

(6)

Production Functions Production Functions

One input, one output

y = f(x) is the production Output Level

One input, one output

production function.

y’ function.

y’

y’ = f(x’) is the maximal output level obtainable output level obtainable from x’ input units.

x’ x

Input Level

© 2010 W. W. Norton & Company, Inc. 6

Input Level

(7)

Technology Sets Technology Sets

A production plan is an input bundle and an output level; (x , … , x , y).

and an output level; (x1, … , xn, y).

A production plan is feasible if

A production plan is feasible if

y ≤≤≤≤ f x ( 1 , L , x n ) y ≤≤≤≤ f x ( 1 , L , x n )

The collection of all feasible

production plans is the technology set.

© 2010 W. W. Norton & Company, Inc. 7

(8)

Technology Sets Technology Sets

One input, one output

y = f(x) is the production Output Level

One input, one output

production function.

y’ function.

y’

y’ = f(x’) is the maximal output level obtainable y”

output level obtainable from x’ input units.

y” = f(x’) is an output level y” y” = f(x’) is an output level

that is feasible from x’

input units.

x’ x

Input Level

input units.

© 2010 W. W. Norton & Company, Inc. 8

Input Level

(9)

Technology Sets Technology Sets

The technology set is The technology set is

T ==== { ( x , , x , ) | y y ≤≤≤≤ f x ( , , x ) a n d

T x x y y f x x a n d

x x

n n

==== ≤≤≤≤

≥≥≥≥ ≥≥≥≥

{ ( , , , ) | ( , , )

, , } .

1 1

0 0

L L

x

1

≥≥≥≥ 0 , K K , x

n

≥≥≥≥ 0 } .

© 2010 W. W. Norton & Company, Inc. 9

(10)

Technology Sets Technology Sets

One input, one output

Output Level

One input, one output

y’

y’

The technology y”

The technology y” set

x’ x

Input Level

© 2010 W. W. Norton & Company, Inc. 10

Input Level

(11)

Technology Sets Technology Sets

One input, one output

Output Level

One input, one output

y’ Technically

efficient plans y’

The technology efficient plans

y”

The technology Technically set

y” Technically

inefficient plans

x’ x

Input Level plans

© 2010 W. W. Norton & Company, Inc. 11

Input Level

(12)

Technologies with Multiple Technologies with Multiple

Inputs

What does a technology look like when there is more than one input?

when there is more than one input?

The two input case: Input levels are

The two input case: Input levels are x11 and x22. Output level is y.

Suppose the production function is

y ==== ==== f x ( (

11

, , x

22

) ) ==== ==== 2 2 x

11 / 31

x

1 / 322

. .

© 2010 W. W. Norton & Company, Inc. 12

(13)

Technologies with Multiple Technologies with Multiple

Inputs

E.g. the maximal output level

E.g. the maximal output level possible from the input bundle (x , x ) = (1, 8) is

(x1, x2) = (1, 8) is

y ==== 2 x 1 / 3 x 1 / 3 ==== ××××2 1 1 / 3 ×××× 8 1 / 3 ==== ×××× ×××× ====2 1 2 4 . And the maximal output level

y ==== 2 x 11 / 3 x 1 / 32 ==== ××××2 1 1 / 3 ×××× 8 1 / 3 ==== ×××× ×××× ====2 1 2 4 .

And the maximal output level possible from (x1,x2) = (8,8) is possible from (x1,x2) = (8,8) is

y ==== 2 x

11 / 3

x

1 / 32

==== ×××× 2 8

1 / 3

×××× 8

1 / 3

==== ×××× ×××× ==== 2 2 2 8 .

y ==== 2 x

1

x

2

==== ×××× 2 8 ×××× 8 ==== ×××× ×××× ==== 2 2 2 8 .

© 2010 W. W. Norton & Company, Inc. 13

(14)

Technologies with Multiple Technologies with Multiple

Inputs

Output, y

x2 (8,1)

(8,8) x1

© 2010 W. W. Norton & Company, Inc. 14

(15)

Technologies with Multiple Technologies with Multiple

Inputs

The y output unit isoquant is the set of all input bundles that yield at most of all input bundles that yield at most the same output level y.

the same output level y.

© 2010 W. W. Norton & Company, Inc. 15

(16)

Isoquants with Two Variable Isoquants with Two Variable

Inputs

x2

y ≡ 8≡ 8≡ 8≡ 8 y ≡ 8≡ 8≡ 8≡ 8

y ≡ 4≡ 4≡ 4≡ 4 x1

© 2010 W. W. Norton & Company, Inc. 16

(17)

Isoquants with Two Variable Isoquants with Two Variable

Inputs

Isoquants can be graphed by adding an output level axis and displaying an output level axis and displaying each isoquant at the height of the each isoquant at the height of the isoquant’s output level.

© 2010 W. W. Norton & Company, Inc. 17

(18)

Isoquants with Two Variable Isoquants with Two Variable

Inputs

Output, y

y ≡ 8≡ 8≡ 8≡ 8

x2 y ≡ 4≡ 4≡ 4≡ 4

x1

© 2010 W. W. Norton & Company, Inc. 18

(19)

Isoquants with Two Variable Isoquants with Two Variable

Inputs

More isoquants tell us more about the technology.

the technology.

© 2010 W. W. Norton & Company, Inc. 19

(20)

Isoquants with Two Variable Isoquants with Two Variable

Inputs

x2

y ≡ 8≡ 8≡ 8≡ 8 y ≡ 8≡ 8≡ 8≡ 8

y ≡ 6≡ 6≡ 6≡ 6 y ≡ 4≡ 4≡ 4≡ 4 y ≡ 6≡ 6≡ 6≡ 6 y ≡ 2≡ 2≡ 2≡ 2 x1 y ≡ 2≡ 2≡ 2≡ 2

© 2010 W. W. Norton & Company, Inc. 20

(21)

Isoquants with Two Variable Isoquants with Two Variable

Inputs

Output, y

y ≡ 8≡ 8≡ 8≡ 8 y ≡ 6≡ 6≡ 6≡ 6

x2 y ≡ 4≡ 4≡ 4≡ 4 y ≡ 2≡ 2≡ 2≡ 2

x1

© 2010 W. W. Norton & Company, Inc. 21

(22)

Technologies with Multiple Technologies with Multiple

Inputs

The complete collection of isoquants

The complete collection of isoquants is the isoquant map.

is the isoquant map.

The isoquant map is equivalent to

the production function -- each is the other.

other.

E.g.E.g.

y y ==== ==== f f ( ( x x

11

, , x x

22

) ) ==== ==== 2 2 x x

111 / 3

x x

122 / 3

© 2010 W. W. Norton & Company, Inc. 22

(23)

Technologies with Multiple Technologies with Multiple

Inputs

x2

y x1

y

© 2010 W. W. Norton & Company, Inc. 23

(24)

Technologies with Multiple Technologies with Multiple

Inputs

x x2

y

x1

© 2010 W. W. Norton & Company, Inc. 24

(25)

Technologies with Multiple Technologies with Multiple

Inputs

x2

y y

x1

© 2010 W. W. Norton & Company, Inc. 25

(26)

Technologies with Multiple Technologies with Multiple

Inputs

x2

y y

x1

© 2010 W. W. Norton & Company, Inc. 26

(27)

Technologies with Multiple Technologies with Multiple

Inputs

x2

y

x1

© 2010 W. W. Norton & Company, Inc. 27

(28)

Technologies with Multiple Technologies with Multiple

Inputs

x2 x2

y

x1

© 2010 W. W. Norton & Company, Inc. 28

(29)

Technologies with Multiple Technologies with Multiple

Inputs

y y

x1

© 2010 W. W. Norton & Company, Inc. 29

(30)

Technologies with Multiple Technologies with Multiple

Inputs

y y

x1

© 2010 W. W. Norton & Company, Inc. 30

(31)

Technologies with Multiple Technologies with Multiple

Inputs

y

x1

© 2010 W. W. Norton & Company, Inc. 31

(32)

Technologies with Multiple Technologies with Multiple

Inputs

y

x1

© 2010 W. W. Norton & Company, Inc. 32

(33)

Technologies with Multiple Technologies with Multiple

Inputs

y

x1

© 2010 W. W. Norton & Company, Inc. 33

(34)

Technologies with Multiple Technologies with Multiple

Inputs

y

x1

© 2010 W. W. Norton & Company, Inc. 34

(35)

Technologies with Multiple Technologies with Multiple

Inputs

y

x1

© 2010 W. W. Norton & Company, Inc. 35

(36)

Technologies with Multiple Technologies with Multiple

Inputs

y

x1

© 2010 W. W. Norton & Company, Inc. 36

(37)

Technologies with Multiple Technologies with Multiple

Inputs

y y

x1

© 2010 W. W. Norton & Company, Inc. 37

(38)

Technologies with Multiple Technologies with Multiple

Inputs

y y

x1

© 2010 W. W. Norton & Company, Inc. 38

(39)

Cobb-Douglas Technologies Cobb-Douglas Technologies

A Cobb-Douglas production function is of the form

is of the form

y ==== A x a 1 x a 2 ×××× ××××L x a n .

E.g.

y ==== A x 1a 1 x a2 2 ×××× ××××L x na n .

E.g.

y ==== x

11 / 3

x

1 / 32

with

y ==== x

1

x

2

n ==== 2 A ==== 1 a ==== 1 a n d a ==== 1

1 2

, , .

n ==== 2 A ==== 1 a ==== a n d a ====

3 3

1 2

, , .

© 2010 W. W. Norton & Company, Inc. 39

(40)

Cobb-Douglas Technologies

x2

All isoquants are hyperbolic,

Cobb-Douglas Technologies

All isoquants are hyperbolic, asymptoting to, but never

asymptoting to, but never touching any axis.

a a

====

y ==== x

1a 1

x

a2 2

x1

© 2010 W. W. Norton & Company, Inc. 40

(41)

Cobb-Douglas Technologies

x2

All isoquants are hyperbolic,

Cobb-Douglas Technologies

All isoquants are hyperbolic, asymptoting to, but never

asymptoting to, but never touching any axis.

a a

====

y ==== x

1a 1

x

a2 2

x 1a 1 x a2 2 ==== y "

x 1 1 x 2 2 ==== y "

x1

© 2010 W. W. Norton & Company, Inc. 41

(42)

Cobb-Douglas Technologies

x2

All isoquants are hyperbolic,

Cobb-Douglas Technologies

All isoquants are hyperbolic, asymptoting to, but never

asymptoting to, but never touching any axis.

a a

====

y ==== x

1a 1

x

a2 2

x 1a 1 x a2 2 ==== y "

x 1a 1 x a2 2 ==== y ' x 1 1 x 2 2 ==== y "

x1

x 1 x 2 ==== y '

© 2010 W. W. Norton & Company, Inc. 42

(43)

Cobb-Douglas Technologies

x2

All isoquants are hyperbolic,

Cobb-Douglas Technologies

All isoquants are hyperbolic, asymptoting to, but never

asymptoting to, but never touching any axis.

a a

y " > y '

y ==== ==== x

1a 1

x

a2 2

x 1a 1 x a2 2 ==== y "

y " > '

x 1a 1 x a2 2 ==== y ' x 1 1 x 2 2 ==== y "

x1

x 1 x 2 ==== y '

© 2010 W. W. Norton & Company, Inc. 43

(44)

Fixed-Proportions Technologies Fixed-Proportions Technologies

A fixed-proportions production function is of the form

function is of the form

y ==== m i n { a x1 1 , a x2 2 , L , a xn n } . E.g.

y ==== m i n { a x1 1 , a x2 2 , L , a xn n } .

E.g.

y ==== m i n { x

1

, 2 x

2

}

with

y ==== m i n { x

1

, 2 x

2

}

n ==== 2 , a 1 ==== 1 a n d a 2 ==== 2 . n ==== 2 , a 1 ==== 1 a n d a 2 ==== 2 .

© 2010 W. W. Norton & Company, Inc. 44

(45)

Fixed-Proportions Technologies Fixed-Proportions Technologies

x

y ==== m i n { x

1

, 2 x

2

}

x2

y ==== m i n { x

1

, 2 x

2

}

x1 = 2x2

min{x1,2x2} = 14 4

7

min{x ,2x } = 8 24 min{x1,2x2} = 8

min{x1,2x2} = 4 x1

4 8 14

min{x1,2x2} = 4

© 2010 W. W. Norton & Company, Inc. 45

(46)

Perfect-Substitutes Technologies Perfect-Substitutes Technologies

A perfect-substitutes production function is of the form

function is of the form

y ==== a x1 1 ++++ a x2 2 ++++ L ++++ a n x n .

E.g.

y ==== a x1 1 ++++ a x2 2 ++++ L ++++ a n x n .

E.g.

y ==== x

1

++++ 3 x

2

with

y ==== x

1

++++ 3 x

2

n ==== 2 , a 1 ==== 1 a n d a 2 ==== 3 . n ==== 2 , a 1 ==== 1 a n d a 2 ==== 3 .

© 2010 W. W. Norton & Company, Inc. 46

(47)

Perfect-Substitution Perfect-Substitution

Technologies

x

y ==== x

1

++++ 3 x

2

x2

x1 + 3x2 = 18 x1 + 3x2 = 18

x1 + 3x2 = 36

8

x1 + 3x2 = 36

x1 + 3x2 = 48

6

8 x1 + 3x2 = 48

All are linear and parallel

3

6 All are linear and parallel

9 18 24 x1

© 2010 W. W. Norton & Company, Inc. 47

(48)

Marginal (Physical) Products Marginal (Physical) Products

y ==== f x (

1

, L , x

n

)

The marginal product of input i is the

y ==== f x (

1

, L , x

n

)

The marginal product of input i is the rate-of-change of the output level as rate-of-change of the output level as the level of input i changes, holding all other input levels fixed.

all other input levels fixed.

That is,

y

M P ==== ∂∂∂∂

That is,

i

i

x

M P y

∂∂∂∂

==== ∂∂∂∂

x

i

∂∂∂∂

© 2010 W. W. Norton & Company, Inc. 48

(49)

Marginal (Physical) Products Marginal (Physical) Products

E.g. if E.g. if

y ==== f x( 1 , x 2 ) ==== x 11 / 3 x 22 3/ y ==== f x( 1 , x 2 ) ==== x 1 x 2

then the marginal product of input 1 is

© 2010 W. W. Norton & Company, Inc. 49

(50)

Marginal (Physical) Products Marginal (Physical) Products

E.g. if E.g. if

y ==== f x( 1 , x 2 ) ==== x 11 / 3 x 22 3/ y ==== f x( 1 , x 2 ) ==== x 1 x 2

then the marginal product of input 1 is

M P y

x x x

1 1 2 3

22 3

1

====

∂∂∂∂

==== 3 −−−−

∂∂∂∂

x / /

1

1

1 2

∂∂∂∂

3

© 2010 W. W. Norton & Company, Inc. 50

(51)

Marginal (Physical) Products Marginal (Physical) Products

E.g. if E.g. if

y ==== f x( 1 , x 2 ) ==== x 11 / 3 x 22 3/ y ==== f x( 1 , x 2 ) ==== x 1 x 2

then the marginal product of input 1 is

M P y

x x x

1 1 2 3

22 3

1

====

∂∂∂∂

==== 3 −−−−

∂∂∂∂

x / /

1

1

1 2

∂∂∂∂

3

and the marginal product of input 2 is and the marginal product of input 2 is

© 2010 W. W. Norton & Company, Inc. 51

(52)

Marginal (Physical) Products Marginal (Physical) Products

E.g. if E.g. if

y ==== f x( 1 , x 2 ) ==== x 11 / 3 x 22 3/ y ==== f x( 1 , x 2 ) ==== x 1 x 2

then the marginal product of input 1 is

M P y

x x x

1 1 2 3

22 3

1

====

∂∂∂∂

==== 3 −−−−

∂∂∂∂

x / /

1

1

1 2

∂∂∂∂

3

and the marginal product of input 2 is and the marginal product of input 2 is

M P y

x x x

2 11 / 3

2 1 / 3

2

==== ∂∂∂∂ ==== 3 −−−−

∂∂∂∂ .

M P 2 x x x

2 1 2

==== ==== 3

∂∂∂∂ .

© 2010 W. W. Norton & Company, Inc. 52

(53)

Marginal (Physical) Products Marginal (Physical) Products

Typically the marginal product of one Typically the marginal product of one

input depends upon the amount used of input depends upon the amount used of other inputs. E.g. if

M P 1 x 2 3 x 2 3

==== −−−− / /

M P1 1 x 1 2 3 x 22 3

==== 3 −−−− / / then,

M P 1 x 2 3 2 3 4 x 2 3

==== −−−− / / ==== −−−− /

M P1 1 x 1 2 3 2 3 x 1 2 3

3 8 4

==== −−−− / / ==== 3 −−−− /

and if x = 27 then if x2 = 8,

and if x2 = 27 then

M P 1 x 2 3 2 3 x 2 3

2 7 3

==== −−−− / / ==== −−−− / .

M P1 1 x 1 2 3 2 3 x 1 2 3

3 2 7 3

==== −−−− / / ==== −−−− / .

© 2010 W. W. Norton & Company, Inc. 53

(54)

Marginal (Physical) Products Marginal (Physical) Products

The marginal product of input i is

diminishing if it becomes smaller as diminishing if it becomes smaller as the level of input i increases. That is, the level of input i increases. That is,

if 2





i y y

M P ∂∂∂∂ ∂∂∂∂ ∂∂∂∂

∂∂∂∂ 0 .

2 2 <<<<

 ====









==== 

i i i

i i

x y x

y x

x M P

∂∂∂∂

∂∂∂∂

∂∂∂∂

∂∂∂∂

∂∂∂∂

∂∂∂∂

∂∂∂∂

∂∂∂∂



 i i

i

i x x x

x ∂∂∂∂ ∂∂∂∂ ∂∂∂∂

∂∂∂∂

© 2010 W. W. Norton & Company, Inc. 54

(55)

Marginal (Physical) Products Marginal (Physical) Products

E.g. if y ==== x 1 / 3 x 2 3/ then M P 1 x 2 3 x 2 3

==== −−−− / / and M P ==== 2 x 1 / 3 x −−−− 1 / 3 E.g. if y ==== x 11 / 3 x 22 3/ then

M P 1 1 x 1 2 3 x 22 3

==== 3 −−−− / / M P 2 2 x 11 / 3 x 2 1 / 3

==== 3 −−−−

and

© 2010 W. W. Norton & Company, Inc. 55

(56)

Marginal (Physical) Products Marginal (Physical) Products

E.g. if y ==== x 1 / 3 x 2 3/ then M P 1 x 2 3 x 2 3

==== −−−− / / and M P ==== 2 x 1 / 3 x −−−− 1 / 3 E.g. if y ==== x 11 / 3 x 22 3/ then

M P 1 1 x 1 2 3 x 22 3

==== 3 −−−− / / M P 2 2 x 11 / 3 x 2 1 / 3

==== 3 −−−−

and so ∂∂∂∂ M P 2

so ∂∂∂∂

∂∂∂∂

M P

x 1 x x

1 1 5 3

22 3

2

9 0

==== −−−− −−−− / / <<<<

∂∂∂∂ x 1 9

© 2010 W. W. Norton & Company, Inc. 56

(57)

Marginal (Physical) Products Marginal (Physical) Products

E.g. if y ==== x 1 / 3 x 2 3/ then M P 1 x 2 3 x 2 3

==== −−−− / / and M P ==== 2 x 1 / 3 x −−−− 1 / 3 E.g. if y ==== x 11 / 3 x 22 3/ then

M P 1 1 x 1 2 3 x 22 3

==== 3 −−−− / / M P 2 2 x 11 / 3 x 2 1 / 3

==== 3 −−−−

and so ∂∂∂∂ M P 2

so ∂∂∂∂

∂∂∂∂

M P

x 1 x x

1 1 5 3

22 3

2

9 0

==== −−−− −−−− / / <<<<

∂∂∂∂ x 1 9

∂∂∂∂ M P

x x

2 2 1 / 3 4 3

==== −−−− −−−− / <<<< 0 .

and ∂∂∂∂

∂∂∂∂

M P

x 2 x x

2 11 / 3

2 4 3

2

9 0

==== −−−− −−−− / <<<< .

© 2010 W. W. Norton & Company, Inc. 57

(58)

Marginal (Physical) Products Marginal (Physical) Products

E.g. if y ==== x 1 / 3 x 2 3/ then M P 1 x 2 3 x 2 3

==== −−−− / / and M P ==== 2 x 1 / 3 x −−−− 1 / 3 E.g. if y ==== x 11 / 3 x 22 3/ then

M P 1 1 x 1 2 3 x 22 3

==== 3 −−−− / / M P 2 2 x 11 / 3 x 2 1 / 3

==== 3 −−−−

and so ∂∂∂∂ M P 2

so ∂∂∂∂

∂∂∂∂

M P

x 1 x x

1 1 5 3

22 3

2

9 0

==== −−−− −−−− / / <<<<

∂∂∂∂ x 1 9

∂∂∂∂ M P

x x

2 2 1 / 3 4 3

==== −−−− −−−− / <<<< 0 .

and ∂∂∂∂

∂∂∂∂

M P

x 2 x x

2 11 / 3

2 4 3

2

9 0

==== −−−− −−−− / <<<< .

Both marginal products are diminishing.

Both marginal products are diminishing.

© 2010 W. W. Norton & Company, Inc. 58

(59)

Returns-to-Scale Returns-to-Scale

Marginal products describe the change in output level as a single change in output level as a single input level changes.

input level changes.

Returns-to-scale describes how the output level changes as all input

levels change in direct proportion levels change in direct proportion (e.g. all input levels doubled, or halved).

halved).

© 2010 W. W. Norton & Company, Inc. 59

(60)

Returns-to-Scale Returns-to-Scale

If, for any input bundle (x ,…,x ), If, for any input bundle (x1,…,xn),

f k x( 1 , k x 2 , L , k x n ) ==== k f x( 1 , x 2 , L , x n ) f k x( 1 , k x 2 , L , k x n ) ==== k f x( 1 , x 2 , L , x n ) then the technology described by the then the technology described by the production function f exhibits constant returns-to-scale.

returns-to-scale.

E.g. (k = 2) doubling all input levels E.g. (k = 2) doubling all input levels doubles the output level.

© 2010 W. W. Norton & Company, Inc. 60

(61)

Returns-to-Scale Returns-to-Scale

One input, one output

Output Level

One input, one output

y = f(x) 2y’

2y’

Constant

y’

Constant

returns-to-scale

x’ x

Input Level 2x’

© 2010 W. W. Norton & Company, Inc. 61

Input Level

(62)

Returns-to-Scale Returns-to-Scale

If, for any input bundle (x ,…,x ), If, for any input bundle (x1,…,xn),

f k x( 1 , k x 2 , L , k x n ) <<<< k f x( 1 , x 2 , L , x n ) f k x( 1 , k x 2 , L , k x n ) <<<< k f x( 1 , x 2 , L , x n )

then the technology exhibits diminishing then the technology exhibits diminishing returns-to-scale.

E.g. (k = 2) doubling all input levels less E.g. (k = 2) doubling all input levels less than doubles the output level.

than doubles the output level.

© 2010 W. W. Norton & Company, Inc. 62

(63)

Returns-to-Scale Returns-to-Scale

One input, one output

Output Level

One input, one output

y = f(x) 2f(x’)

f(2x’)

Decreasing

f(x’)

Decreasing

returns-to-scale

x’ x

Input Level 2x’

© 2010 W. W. Norton & Company, Inc. 63

Input Level

(64)

Returns-to-Scale Returns-to-Scale

If, for any input bundle (x ,…,x ), If, for any input bundle (x1,…,xn),

f k x( 1 , k x 2 , L , k x n ) >>>> k f x( 1 , x 2 , L , x n ) f k x( 1 , k x 2 , L , k x n ) >>>> k f x( 1 , x 2 , L , x n ) then the technology exhibits increasing then the technology exhibits increasing returns-to-scale.

E.g. (k = 2) doubling all input levels E.g. (k = 2) doubling all input levels more than doubles the output level.

more than doubles the output level.

© 2010 W. W. Norton & Company, Inc. 64

(65)

Returns-to-Scale Returns-to-Scale

One input, one output

Output Level

One input, one output

y = f(x)

Increasing

returns-to-scale

f(2x’)

returns-to-scale

2f(x’) f(x’) 2f(x’)

x’ x

Input Level

2x’

© 2010 W. W. Norton & Company, Inc. 65

Input Level

(66)

Returns-to-Scale Returns-to-Scale

A single technology can ‘locally’

exhibit different returns-to-scale.

exhibit different returns-to-scale.

© 2010 W. W. Norton & Company, Inc. 66

(67)

Returns-to-Scale Returns-to-Scale

One input, one output

Output Level

One input, one output

y = f(x)

Increasing y = f(x)

Increasing

returns-to-scale

Decreasing returns-to-scale

Decreasing

returns-to-scale

x Input Level

© 2010 W. W. Norton & Company, Inc. 67

Input Level

(68)

Examples of Returns-to-Scale Examples of Returns-to-Scale

The perfect-substitutes production

y ==== a x ++++ a x ++++ ++++ a x .

The perfect-substitutes production function is

y ==== a x1 1 ++++ a x2 2 ++++ L ++++ a n x n .

Expand all input levels proportionately Expand all input levels proportionately by k. The output level becomes

by k. The output level becomes

a 1 ( k x 1 ) ++++ a 2 ( k x 2 ) ++++ L ++++ a n ( k x n )

© 2010 W. W. Norton & Company, Inc. 68

(69)

Examples of Returns-to-Scale Examples of Returns-to-Scale

The perfect-substitutes production

y ==== a x ++++ a x ++++ ++++ a x .

The perfect-substitutes production function is

y ==== a x1 1 ++++ a x2 2 ++++ L ++++ a n x n .

Expand all input levels proportionately Expand all input levels proportionately by k. The output level becomes

by k. The output level becomes

a k x a k x a k x

k a x a x a x

n n

n n

1 1 2 2

1 1 2 2

( ) ( ) ( )

( )

++++ ++++ ++++

==== ++++ ++++ ++++

L

k a x( 1 1 a x2 2 L a xn n )

==== ++++ ++++ L ++++

© 2010 W. W. Norton & Company, Inc. 69

(70)

Examples of Returns-to-Scale Examples of Returns-to-Scale

The perfect-substitutes production

y ==== a x ++++ a x ++++ ++++ a x .

The perfect-substitutes production function is

y ==== a x1 1 ++++ a x2 2 ++++ L ++++ a n x n .

Expand all input levels proportionately Expand all input levels proportionately by k. The output level becomes

by k. The output level becomes

a k x a k x a k x

k a x a x a x

n n

n n

1 1 2 2

1 1 2 2

( ) ( ) ( )

( )

++++ ++++ ++++

==== ++++ ++++ ++++

L

k a x a x L a x

k y

n n

1 1 2 2

( )

.

==== ++++ ++++ ++++

====

L

The perfect-substitutes production

function exhibits constant returns-to-scale.

© 2010 W. W. Norton & Company, Inc. 70

function exhibits constant returns-to-scale.

(71)

Examples of Returns-to-Scale Examples of Returns-to-Scale

The perfect-complements production

y ==== m i n { a x , a x , , a x } .

The perfect-complements production function is

y ==== m i n { a x1 1 , a x2 2 , L , a n x n } .

Expand all input levels proportionately Expand all input levels proportionately by k. The output level becomes

by k. The output level becomes

m i n { a 1 ( k x 1 ) , a 2 ( k x 2 ) , L , a n ( k x n ) }

© 2010 W. W. Norton & Company, Inc. 71

(72)

Examples of Returns-to-Scale Examples of Returns-to-Scale

The perfect-complements production

y ==== m i n { a x , a x , , a x } .

The perfect-complements production function is

y ==== m i n { a x1 1 , a x2 2 , L , a n x n } .

Expand all input levels proportionately Expand all input levels proportionately by k. The output level becomes

by k. The output level becomes

m i n { ( ) , ( ) , , ( ) }

( m i n { , , , } )

a k x a k x a k x

k a x a x a x

n n

n n

1 1 2 2

1 1 2 2

L

==== k ( m i n { a x1 1 , a x2 2 , LL , a xn n } )

====

© 2010 W. W. Norton & Company, Inc. 72

(73)

Examples of Returns-to-Scale Examples of Returns-to-Scale

The perfect-complements production

y ==== m i n { a x , a x , , a x } .

The perfect-complements production function is

y ==== m i n { a x1 1 , a x2 2 , L , a n x n } .

Expand all input levels proportionately Expand all input levels proportionately by k. The output level becomes

by k. The output level becomes

m i n { ( ) , ( ) , , ( ) }

( m i n { , , , } )

a k x a k x a k x

k a x a x a x

n n

n n

1 1 2 2

1 1 2 2

L

==== ( m i n { , , L , } )

.

k a x a x a x

k y

n n

1 1 2 2 L

====

====

The perfect-complements production

function exhibits constant returns-to-scale.

© 2010 W. W. Norton & Company, Inc. 73

function exhibits constant returns-to-scale.

(74)

Examples of Returns-to-Scale Examples of Returns-to-Scale

The Cobb-Douglas production function is

y ==== x 1a 1 x a2 2 L x na n .

The Cobb-Douglas production function is

1 2 n

Expand all input levels proportionately by k. The output level becomes

by k. The output level becomes

( k x 1 ) a 1 ( k x 2 ) a 2 L ( k x n ) a n ( k x 1 ) ( k x 2 ) L ( k x n )

© 2010 W. W. Norton & Company, Inc. 74

(75)

Examples of Returns-to-Scale Examples of Returns-to-Scale

The Cobb-Douglas production function is

y ==== x 1a 1 x a2 2 L x na n .

The Cobb-Douglas production function is

1 2 n

Expand all input levels proportionately by k. The output level becomes

by k. The output level becomes

( k x 1 ) a 1 ( k x 2 ) a 2 L ( k x n ) a n ( k x ) ( k x ) ( k x )

k k k x x x

n

a a a n a a a n

1 2

1 2 1 2

L

L L

====

© 2010 W. W. Norton & Company, Inc. 75

(76)

Examples of Returns-to-Scale Examples of Returns-to-Scale

The Cobb-Douglas production function is

y ==== x 1a 1 x a2 2 L x na n .

The Cobb-Douglas production function is

1 2 n

Expand all input levels proportionately by k. The output level becomes

by k. The output level becomes

( k x 1 ) a 1 ( k x 2 ) a 2 L ( k x n ) a n ( k x ) ( k x ) ( k x )

k k k x x x

n

a a a n a a a n

1 2

1 2 1 2

L

L L

====

k a 1 a 2 L a n x 1a 1 x a2 2 L x na n

==== ++++ ++++ ++++

© 2010 W. W. Norton & Company, Inc. 76

Cytaty