Competition Flashcards
Perfect competition
Firms are price takers for both inputs and outputs; can’t independently influence the price that is charged for their goods or for the goods they need as inputs.
This is true under two conditions:
Demand for firm’s outputs = perfectly elastic
Supply for the firm’s inputs = perfectly elastic
Demand is perfectly elastic when…
Consumers believe that firms sell identical products, consumers know all prices, and there are low transaction costs (i.e. it’s easy/low cost to shop across firms)
Long-run cost curve
Cost minimizing way to produce any one of the given number of quantities; long-run expansion path
Firm’s demand curve (in relation to the whole market)
q(p) = Q(p) - S(p)
firm’s demand curve = market demand minus supply of all other firms in the market
The elasticity of demand for any given firm equation
If q = Q/N (all firms are identical) and supply for all firms is S = (n-1)q
Then, we can say that the elasticity of demand facing a given firm E = n * elasticity fo demand for the whole market minus (N-1) * elasticity of supply
Ei = nE - (n-1)*elasticity of supply
Why is the elasticity of demand of ONE FIRM so much larger than the elasticity of demand for the MARKET?
The elasticity of demand facing a single firm in a perfectly competitive market is much larger in magnitude (i.e. more negative) than the market elasticity of demand. This is because, with a small price change, the consumer will easily abandon the firm and buy an identical product from a competitor. This is true even for inelastic goods, such as life-saving drugs.
Profit equation
Profit (pi) = Revenues (R) - Cost (C)
Accounting profits vs. economic profits
Economist profits measure the opportunity costs that are also paid when a decision is made, not just the financial costs
How do firms maximize profit in the short run? (equation)
The profit-maximizing firm will always set Marginal Revenue MR = Marginal Cost MC
dR/dq = dC/dq at the optimum
In a perfectly competitive market, what is the revenue I earn on the next unit I sell?
MC = price because MR is always the price
Not true in a non-perfectly competitive market
How does a firm decide whether or not to keep producing?
At the margin! If the next unit they produce has a marginal cost higher than the marginal revenue (equal to price in perf competitive market) then they won’t produce that unit (even if TC < TR)
Why would you stay open in the short run if your profits are negative?
If its still more than the losses you face when you produce q = 0 (shutdown) it makes sense to stay open, even if the profit is negative.
Only want to shutdown if p*q < VC
The revenues I earn are less than the actual cost of production beyond the fixed cost, i.e. variable costs
so, if price < AVC you’ll shutdown
**At the margin, if you lose money
A firm’s supply curve is actually equal to…
the firm’s marginal cost curve
As you have more firms, what happens to the shape of the market’s supply curve?
It becomes increasingly flatter; assuming that we have identical firms
The horizontal sum of each firms’ supply
n * firm’s supply
Differences between LR and SR competition?
Simpler shutdown rule: If you’re losing money, you should shut down. In the SR, p < AVC but in the LR, p< AC you will shut down. If revenues are less than costs, you shut down.
We also now have entry and exit - firms can decide on whether or not to enter or leave; in a competitive market, firms will enter if profits being made & exit if profits are being lost
In the LR, firms will enter and exit until…
profits are driven to zero.
Where do profits = 0? (graphically)
MC = AVC; will be the minimum average costs
Production possibilities frontier
shows the maximum combination of outputs that can be produced for any combination of inputs
Linear PPF vs. PPF with economies of scope
Linear PPF - a minute spent on one thing is equally productive to a minute spent on the other thing - so you can choose any combination you want & it’s equally efficient
PPF with economies of scope: outward bending shape, doing a combination makes you more productive in both things; better off doing some of each
Economy of scope
Doing one thing raises your productivity in the other
The cost of producing just q2 + cost of producing just q1 is greater than the cost of producing q1 & q2
Diseconomy of scope
Producing each good by itself costs less than producing both; better of just producing one or the other (less productive when producing both)
Inward bending shape