Advanced behaveriol economics Flashcards
Myopic loss aversion
People take more risk if they consider several decisions together than if they take them separately
Risk
Probabilities are KNOWN
Uncertainty
Probabilities are unknown
Prospect/lottery
List of consequences with associated probabilities
Example: (50%:€1 ; 50%:€-0,5)
Preference notations
p>q
p~q
p>q p strictly preferred to q
p~q indifference between p and q
Monotonicity
- two lotteries L1 and L2
- if no matter what happens, L1 always gives more than L2, then L1 is preferred to L2
St. Petersburg Paradox
- if you play a game with the EV infinite than in reality people will pat less
- EV means that an increase in our wealth of €100 feels the same no matter whether we earn €1000 or €9000 per month.
- Solution: first translate monetary amounts into utilities, or subjective values, of monetary amounts
Certainty equivalent (CE)
Outcome that makes a person indifferent between receiving the prospect or receiving CE for sure.
Risk premium
- RP=EV-CE
- risk premium tells us how much of the expected value of the lottery you are willing to give up in return for getting it for sure instead of facing the risk.
Graph utility
Risk averse
Risk neutral
Risk seeking
Risk averse - concave utility
Risk neutral - linear utility
Risk seeking - convex utility
Coefficient of absolute risk aversion
- r(x)= - ú(x)/u(x)
- when EU holds: the higher the coefficient the more risk averse.
- r measures the concavity of the function
CARA
U(x)=a-be^-cx
U(x)=a+bx
U(x)=a+be^cx
Constant absolute risk aversion
r(x)= c for all x; c is a constant parameter
Decreasing absolute risk aversion may be more plausible than CARA: higher income means lower aversion
CRRA
u(x)=a+bx^1-c
u(x)=a+b ln(x)
u(x)=a-bx^-(c-1)x
- Constant relative risk aversion
- constant coefficient of relative risk aversion r*(x)= x r(x)=c for all x, c is a constant parameter.
- higher x means lower r(x) to keep r*(x) constant
Uniqueness of utility
Utility in EU is unique up to location a and scale b
Measuring utility:
Certainty equivalent method
• fix two outcomes m
Measuring utility:
Probability equivalent method
• fix two outcomes m
Descriptive validity EU
Does everybody have a utility function u that we can use in the EU formula to predict his/her choices?
EU axioms
•Completeness:
For all q,r we have either q>r, or r>q, or both
•transitivity:
For all q, r, s we have: if q >r and r>s, then q>s
•continuity:
For all q,r,s with q>r and r>s there must be a probability p such that (p:q ; 1-p : s) ~ r
•independence: for all q,r,s and all probabilities p w have if q>r then (p:q ; 1-p :s) > (p:r ; 1-p :s), and vice versa
Normative validity of EU
Do we think that an individual should satisfy the following three conditions?
-eu axioms
If yes then heb should behave according to EU, and then we think that the EU is normatively valid.
Allais paradox
- Common consequence effect.
* Violation of independence aciom