1. Short Run and Long Run Costs

2. Production Processes
X-Box Production UQM Technologies Scorpion Factory

3. What would you need to start a Panera?

4. Short Run versus Long Run?
short run - a period of time where some inputs are fixed (capital = building, equipment, etc.)
long run - a period of time in which all inputs can be varied (no inputs are fixed)

5. Short Run Cost Function
Definition:
A function that defines the minimum possible cost of producing each output level when variable factors are employed in the cost-minimizing fashion. (Based on the inability to change the fixed factors)

6. In this case, what is your total product/output (Q)?
Number of Paninis (for simplicity assume that Panera only produces a single product).
In general a firm uses capital, labor and materials to produce the product/output where capital is often fixed in the short run.

7. In Short Run, how does the number of Paninis produced change as you change the number of workers?1 5 2 12 3 20 4 25 28

8. How does output change if you hire one more person?
Depends on how many workers you currently have. Output increases by 5 paninis when you hire the 1st worker, increases by 7 paninis when you hire the 2nd worker, …., and increases 3 paninis when you hire the 5th worker.

9. What happens to “productivity” as the first few employees are hired?
Specialize and marginal product increases.
Marginal Product is the change in total output attributable to the last unit of an input.

10. What would happen to “productivity” if you continued to hire more and more workers?
Marginal product would start to fall because some inputs are fixed in the short run.
Law of diminishing marginal returns OR Law of diminishing marginal product.

11. Fixed Costs, FC (or Total Fixed Costs, TFC)
What costs would you have to pay even if you didn’t produce a single panini?
Fixed Costs, FC (or Total Fixed Costs, TFC)
(often involves building and equipment)
Fixed Costs = Costs that do not change with changes in output

12. What costs would you have to pay only if you produced paninis?
Variable Costs, VC (or Total Variable Costs, TVC)
(often assumed to be labor and material)
Variable Costs = Costs that change with changes in output

13. What costs would increase if we wanted to produce one more panini?
Variable Costs (such as labor and materials)

14. If you hired more and more employees
and the store became more and more crowded until the marginal product of a worker started to fall, what would happen to the cost of producing one more panini (marginal cost)?
Marginal cost = cost of producing an additional unit of output

15. Costs - Fixed costs do not vary with outputQ FC VC TC
AFC
AVC
ATC MC
100 - 50 1
150 30 2 80
180 40 90 20 3
200
33.3
33.33
66.7 10 4
110
210 25
27.5
52.5 5
130
230 26 46
Fixed costs do not vary with output
( )/1=
Variable costs increase by 50 from 0 to 1 unit of output and increases by 30 from 1 to 2 units.
Average Variable Costs (AVC) = Variable Costs/Q so at an output of 2, AVC=80/2=40.
Average Fixed Costs (AFC) = Fixed Costs/Q so at an output of 2, AFC=100/2=50.
Average Total Costs (ATC) = Total Costs/Q so at an output of 2, ATC=180/2=90 or AFC+ATC.

16. Costs Q FC VC TC AFC AVC ATC MC 5 100 130 230 20 26 46 30 6 160 26030 6
160
260
16.7
26.67
43.3 40 7
200
300
14.3
28.57
42.9 50 8
250
350
12.5
31.25
43.8 60 9
310
410
11.1
34.44
45.6 70 10
380
480 38 48

17. TC= ATC*Q
What is happening to TC as Q increases?
Increases!
150
180
480

18. What are total fixed costs in this example?
AFC*Q
100*1=100

19. Spreading a fixed number out
over a larger and larger Q
Why are AFC diminishing?

20. Why is AVC getting closer to ATC?
Because ATC = AVC+AFC
and AFC is getting close to 0

21. Where does the law of diminishing marginal product
set in and how do you know?
Where MC starts increasing!
Why does this happen?
An input is fixed in the short run!

22. Where does MC cross ATC? Where does MC cross AVC?
At their minimums
What is the relationship
between MC and ATC?
MC and AVC?
If MC<ATC, ATC is decreasing
If MC>ATC, ATC is increasing
Same for AVC

23. How do you know this is the short run?
There are fixed costs

24. Fixed Cost versus Sunk Cost
Fixed Cost = costs that do not change with changes in output
Sunk Cost= a cost that is forever lost after it has been paid
Does profit maximizing output depend on whether cost if fixed or sunk given that you produce paninis?
Does the decision whether to produce any paninis depend on whether cost is fixed or sunk? No
Yes

25. Short Run versus Long Run?
short run - a period of time where some inputs are fixed (capital = building, equipment, etc.)
long run - a period of time in which all inputs can be varied (no inputs are fixed)

26. Returns to Scale in Long Run Production
Is the increase in output proportional to the increase in “inputs”?
What is the marginal product of changing ALL inputs?

27. Economies to Scale
Exist when long-run average costs decline as output is increased.
Example in other words: to double output, you don’t have to double costs
Example in other words: if you double costs, you more than double the output

28. Why does there exist Economies of Scale?
Specialization in production - get more productive if specialize
Can spread some costs over everything (ex: advertising, R&D, capital investments)
Can command quantity discounts from suppliers

29. Diseconomies of Scale
Exist when long-run average costs rise as output is increased.
Example in other words: to double output, you have to more than double costs
Example in other words: if you double costs, you cannot double the output

30. Why Diseconomies of Scale?
Monitoring
Morale

31. Constant Returns to Scale
Exist when long-run average costs remain constant as output is increased.
Example in other words: to double output, you have to double costs

32. General Example – many possible levels of fixed inputs
Long-run ATC - minimum of Short-run ATC
Minimum Efficient Scale –
smallest output where
average costs are minimized
Diseconomies of Scale
Economies of Scale
Constant Returns to Scale