1. AP Microeconomics Unit 3, Days 1 & 2 Rixie
Production & Costs
AP Microeconomics
Unit 3, Days 1 & 2
Rixie

2. A few key terms:
Firm: an organization that utilizes resources to produce a good or service that it hopes to sell profitably
Explicit costs: direct, purchased, out-of- pocket costs. Examples?
Implicit costs: indirect, non-purchased costs.
Includes the costs of the next-best alternatives that have been forgone… the opportunity costs!

3. Lemonade Stand
Carly runs a lemonade stand and sold 1000 cups this month at a price of $1 per cup. What is her total revenue?
TR = $1 x 1000 cups = $1000
She had the following explicit costs this month:
$75 to rent a table; $300 on lemons, sugar, and cups; and $25 for a vendor’s permit.
How might we determine her profit?
Profit = TR – Explicit Costs = $ $75 - $300 - $25 = $600

4. But wait!
What we just determined is called the accounting profit.
We need to know something called the economic profit.
Economic profit =
TR – Explicit cost – Implicit cost
Carly chose to give up working part-time at a bank for $1000/month – an opportunity cost, or an implicit cost.
What is her economic profit?
$ $75 - $300 - $25 - $1000 = -$400 (a loss!)

5. “Nothing is free; it is just non-priced.”
Economists always considers opportunity costs! We will use:
Economic costs: both explicit & implicit costs.
Economic profit:
TR – explicit costs – implicit costs

6. Production Functions vs. Cost Functions
Production functions look at relationships between inputs & output
Cost functions look at relationship between output and costs
Labor
Production Function
Output
Capital

7. Two Types of Inputs (also compare: fixed costs vs. variable costs)
Fixed inputs: resources that go into the production process that can’t be changed in the short run
Variable inputs: resources that can be adjusted in the short run to meet changes in demand
Ex: The firm can’t change the factory size in the short run, but it can add or reduce labor units (employees).
(also compare: fixed costs vs. variable costs)

8. Relationship between Productivity & Cost
High productivity implies low cost!
Inefficiency leads to high production costs – a competitive disadvantage

9. 3 Short-Run Production Measures
Index Card #1 – Total Product (TP)
The total quantity/output of a good produced at each quantity of a resource employed (usually labor)

10. Index Card #2 – Marginal Product (MP)
The change in total product resulting from a change in the input (addition of a worker)
MP = (Change in TP) / (Change in # of Inputs)
If labor is changing one unit at a time, then:
MP = Change in TP

11. Index Card #3 – Average Product (AP)
Total product divided by the number of inputs employed (# of workers)
AP = TP / # of inputs

12. Example: Short-Run Production Measures for the Lemonade Stand over One Month
Units of Labor
Total Product (TP)
Marginal Product (MP)
Average Product (AP)
0 Units
--- 1 10 2 25 3 45 4 60 5 70 6 75 7 8

13. Graph the TP, MP, and AP data from the previous slide
Graph the TP, MP, and AP data from the previous slide. (This is the last slide of day 1.)
Locate the point where the MP & AP curves intersect. What do you notice about this point of intersection?
Look at the marginal product curve as the quantity of inputs increases. What can be said about the change in MP as outputs increase?
Why do you think MP changes the way you observed in the previous question?

14. Law of Diminishing Marginal Returns (1st slide of day 2)
As successive units of a variable resource are added to a fixed resource, the additional output will eventually decrease.
It is not always more efficient to add more inputs, as we learned in the tennis ball game!

15. + Short-Run Costs Total Cost (TC) = Total Fixed Cost (TFC)
Index Card #4 - Total Cost:
Total Cost (TC) = Total Fixed Cost (TFC) +
Total Variable Cost (TVC)

16. Total Variable Cost (TVC)
Example: Total Costs for our Lemonade Stand (add 4 additional columns to the right for later)
Total Product (Q)
Total Fixed Cost (TFC)
Total Variable Cost (TVC)
Total Cost
(TC = TFC + TVC) $6 $0 1 6 5 2 8 3 13 4 19 26 34 7 43

17. Index Card #5 - Marginal Cost (MC)
Marginal Cost (MC) = Change in TC
Change in Q of Output

18. 3 Types of Short-run Average Costs
Index Card #6
Average Fixed Cost (AFC) = TFC / (Q of Output)
or AFC = ATC - AVC
Index Card #7
Average Variable Cost (AVC) = TVC / (Q of Output)
or AVC = ATC - AFC
Index Card #8
Average Total Cost (ATC) = TC / (Q of Output) or ATC = AFC + AVC

19. Example: Marginal & Average Costs for our Lemonade Stand
Total Product
(Q)
TFC
TVC TC MC
AFC
AVC
ATC $6 $0 -- 1 6 5 11 2 8 14 3 13 19 4 25 26 32 34 40 7 43 49

20. MC
Familiarize yourself with these short run cost curves. This is typically how they will look.

21. Short-run & Long-run Decisions
Short run: a time period when at least one production input (plant size) is fixed and cannot be changed to respond to a change in product demand
Long run: a time period that is the amount of time required to change the plant size.

22. Plant Size (Capital) Fixed Costs Variable Costs Entry/Exit of Firms
Short Run
Fixed
Some No
Long Run
Variable
None
All
Yes

23. Long-run costs
In the long run, the firm has enough time to adjust plant capacity.
The firm must ask itself: “At what scale do we want to operate?”

24. Short-run average cost curves are snapshots of the firm’s ability to produce efficiently at the fixed plant size.
If we put these SRAC curves together, we can see a more continuous picture of the firm’s average costs.

26. Economies of scale: downward part of the LRAC curve – LRAC falls as plant size increases (costs go down, output goes up)
Result of specialization and ability to purchase more efficient capital goods
Plant size doubles & total output of the firm more than doubles.

27. Constant returns to scale: occurs when LRAC is constant over a variety of plant sizes (flattest part)
Plant size doubles, and so does the total output.

28. Plant size doubles, and total output less than doubles.
Diseconomies of scale: upward part of the LRAC curve – LRAC rises as plant size increases.
Result of difficulty of managing larger firms (distant management, worker alienation, problems with communication & coordination)
Plant size doubles, and total output less than doubles.