178.307, Markets, Firms and Consumers Lecture 10- Pricing
Dec 27, 2015
Overview
This topic considers the interaction with the firm and the consumer.
We will look at 2 issues:
– Price bundling– Bait and Switch
advertising.
Readings:– See references at end of
lecture.
Administration– Makeup Test is Friday
(19th) at 12 noon, in QB7– It is only available to
students who got less than 60% in Test 1.
Basic Definitions
Commodity Bundling– Many goods are sold in
“packages”– Pure bundling- goods only
available as a package– Mixed bundling- goods
available separately (components) or as package
E.g. Fastfood “Special Meals”
Consumer Surplus– The difference between
what a consumer is willing to pay (reservation price) and what they actually pay (market price)
Price-discrimination– Selling identical units of
output at different prices.– Requires consumers to be
separated.
Forms of Price Discrimination
First Degree– Each consumer is identified
and charged their reservation price.
– All consumer surplus is extracted.
Third Degree– Separate markets are
identified and charged different prices (based on elasticities)
– Arbitrage must not be possible
Second Degree– Firm does not separate
market– Firm sets prices so that
consumers ‘separate’ themselves
– E.g. Two part Tariffs Entry fee to get into
amusement park Fee per ride
– Quantity ‘discounts’.
Commodity-Bundling
Why does a “special-meal” at McDonalds cost less than the components separately?
– Cost savings?– Complements in
consumption?
Adams/Yellen show it is a form of price-discrimination
– Firm does not need to know reservation price
– It’s not illegal (some forms of price discrimination are…)
Yellen/Adams Model 1
Technology– Marginal cost (c1,c2) of
supply is constant, cost of bundle (cB) = c1 + c2.
Indivisibility– Marginal utility of a second
unit of each good = 0.
Independence– Reservation price of bundle
(rB) equals sum of separate reservation price (r1,r2)
These assumptions exclude cost-savings and complementary consumption as explanations for bundling.
Pure Components Strategy
Set a single price on each commodity separately.
– Group A buys both components
– Group B buys only good 2
– Group C buys only good 1
– Group D buys none
r1
r2
p2*
p1*
AB
CD
Pure Bundling Strategy
Offer the two commodities for sale only as a package.
– Group A buys bundle
– Group B does not
A
B
pB*
pB*
r1
r2
Mixed Bundling Strategy
Offer goods as either a package (pB*) or as pure components (p1* or p2*)
pB*
pB*
r1
r2
p2*
p1*
W
0
X
Y Z
A
B
C
D
Consumption Behaviour
Group B- reservation price is below both components and bundled-price
Group A- only buy the bundle
Group C- only buy good 2 Group D- only buy good 1
Each strategy has advantages and disadvantages for the firm.
We establish a bench-mark (pure price discrimination).
Benchmark
Complete Extraction– No consumer realises
any consumer surplus on their purchases.
Exclusion– No consumer consumes
a good (i) if ci > ri.
Inclusion– Any individual whose
reservation price exceeds its cost, consumes the good.
Note: the symbol r or R is used to denote reservation prices
Dilemmas
Pure Components– Achieves exclusion– Cannot achieve both
inclusion and extraction.
Pure bundling– Problem is with
exclusion
Mixed Bundling– Is always more profitable
than pure bundling when Exclusion is violated
woth pure bundling
– Mixed bundling adds more sorting categories.
Illustration
Suppose we have but 4 consumers:
The reservation prices are:
– A- r1=$10, r2=$90
– B- r1=$45, r2=$55
– C- r1=$60, r2=$40
– D- r1=$90, r2=$10
Independence implies that the reservation price for the bundle is the same all consumers. This is for convenience.
Let C1 =20
Let C2 =30
Pure Components Strategy
Profit maximised with p1=$60 and p2=$90
– C and D buy good 1– A buys good 2.– Firm prevents A and D
buying good when r > c.
Profit– 2 units of good 1 ($60-
$20) = $80– 1 unit of good 2 ($90-
$30) = $60– Total = $140
Extraction violated (A) Inclusion violated (B,C)
Pure Bundling Strategy
Profit maximised with pB = $100
Each bundle costs $50. Net profit per unit sale is $50
All consumers buy 1 bundle Profit is $200
Pure bundling avoids excessive violation of inclusion and extraction.
– All consumer surplus extracted here.
Can violate exclusion if costs are relatively high.
– Eg. A consumes good 1 even though reservation price < supply cost.
Mixed Bundling
The rule is that mixed bundling is more profitable than pure bundling when exclusion is a problem.
Suppose the firm charges p1*=90, p2*=90 and pB*=100
Firm sells 2 bundles to B and C (net profit, $100)
Firm sells only good 1 to D (net profit $70)
Firm sells only good 2 to A (net profit $60).
Total profit is $230. All conditions for price
discrimination met.
Bait and Switch
Form of False-Advertising– Low-piced good is advertised– Replaced by different good in show-room
Surprising because false-advertising discourages appropriate buyers
Firms bait and switch to draw a greater number of shoppers
What are conditions that make it profitable?
Simplify the problem
There are two types of commodities (A,B) Consumers have wealth W, and face prices
PA and PB. Let search costs be k.
Utilities
If A consumed, M(W - PA - k)
If B consumed, N(W - PB - k) R(W) if neither A nor B is consumed; no
search occurs R(W-k) if neither A nor B is consumed;
search occurs
Firms
Let γ firms produce A and (1- γ) firms produce B. A potential customer gets a message from one (and
only one) seller The message identifies location of store and
commodity available for sale. After message, the consumer can decide to shop, or
not shop.
Suppose Firm A advertises B
Conditions for sale:
1. N(W – PB - k) > R(W)– Consumer decides to shop
2. M(W - PA - k) > R(W - k)– Condition for buying after search is weaker than
before.
Bait and Switch depicted
N
M
c2 c1
c1
c2
J
L
γM+
(1- γ)max{N,R(w-k)} = R(w)
C1=R(W)
C2=R(W-k)
N(.) is utility from B
M(.) is utility from A
Conclusions
Sellers of A will use bait-and-switch so long as individuals in Zone L exceeds individuals in Zone J.
Most likely when market is ‘dense’ at one end.
Bait and switch requires that A and B be close substitutes.
Search costs crucial– R(W-k) <– M(W-PA-k) <
– R(W)
Can only hold if k>0.
Summary
Bait and switch occurs because
– Sellers gain shoppers by lying
– Once search costs are paid, marginal cost of buying commodity falls
– Firm loses customers who would genuinely desire good.
Only occurs when– Many shoppers prefer a
good to the other– Hence false adverstising
increases number of shoppers
Must involve close substitutes or costly search
Less likely if there are costs of showing good.