Production Theory Flashcards
Production Function
q = f ( L, K)
q= units of output
L, K = labor and capital inputs
Marginal product
the additional output gained from one extra unit of an input, holding the other inputs constant
The marginal product of labor
the additional output gained from one extra unit of labor, holding the other inputs constant
MPL = dQ/dL
The marginal product of capital
the additional output gained from one extra unit of capital, holding the other inputs constant
MPK = dQ/dK
Isoquants
slices of the production function that show combinations of K and L that produces the same level of output “q”
Isoquants are analogous to indifference curves
Their shape is determined by the substitutability between K and L
What is the slope of isoquants called?
the marginal rate of technical substitution (MRTS)
The isoquant exhibits diminishing margins - each additional unit of labor/capital increases q less than the previous unit and is worth less in terms of foregone capital/labor
MRTS equation
MRTS = -MPl / MPk = - (dq/dL)/(dq/dK)
How do you derive MRTS from a production function?
- q = f(L,K)
- Take the total derivative of our production function to see how total output is changing with respect to changes in inputs: dq = (dq/dL) * dL + (dq/dK) * dK
- Then, set dq = 0
So, 0 = (dq/dL) * dL + (dq/dK) * dK - Then rearrange the terms:
dL/dK = - (dq/dL) / (dq/dK) = MRTS
What has to be true in short-run production?
At least one input is fixed; for this course we assume that capital (K) is fixed & that labor is variable
What has to be true in long-run production?
All inputs are variable, firms can fully decide how much capital (K) and labor (L) to hire
Constant returns to scale equation
f ( 2L, 2K ) = 2 f(L,K)
Decreasing returns to scale equation
f (2L, 2K) < 2 f(L,K)
Increase returns to scale equation
f (2L, 2K) > 2 f(L,K)
Fixed costs
costs of inputs that can’t be varied in the short-run; capital
Variable costs
costs of inputs that can be varied in the short-run; labor
Total costs
C = F + VC; sum of fixed and variable costs
Marginal costs
the extra cost for another unit of output
MC = dC/dq where C is the total cost MC = w * 1/MPL => Marginal costs move inversely with marginal product of labor
What is the marginal cost in the short term?
SR MC = dVC/dq
The marginal cost is determined by the increase in the variable cost (since fixed costs do not vary with output)
Average cost
the average cost of production per unit produced
AC = C/q
The average variable cost equation
AVC = VC/q
The average fixed cost equation
AFC = FC/q