Teaching Pack
Valuing Individual Health Outcomes
An educational production of
All materials produced by the Center for Health Decision Science are free and publicly accessible for educational use
These companion slides accompany the videos included in the teaching pack on Valuing Individual Health Outcomes, in which students learn how to assign quantitative values to health outcomes at the individual level, including: expected utility theory, the axioms of this theory, distinguishing between preference-based measures of value and health-related quality of life outcomes, measuring utility using the standard gamble, the time trade-off, and the visual analog scale, and understanding the limitations of these measures.
This teaching pack was developed by Sue J. Goldie and Eve Wittenberg at the Center for Health Decision Science at the Harvard T.H. Chan School of Public Health. The multimedia components were developed as part of a series of pilots while constructing an online course for graduate students in public health.
Citation: Companion Slides. Teaching Pack: Valuing Individual Health Outcomes. Center for Health Decision Science, Harvard T.H. Chan School of Public Health 2017. https://repository.chds.hsph.harvard.edu/repository/2847/.
Valuing Individual Health Outcomes
Upon completion of this teaching pack students should be able to:
1. Define utility.
2. Distinguish between preferences and measures of health status.
3. Define expected utility theory and describe its axioms.
4. Describe how to perform a standard gamble and how to calculate standard gamble utilities.
5. Demonstrate an understanding of the limitations of the standard gamble and the advantages and disadvantages of alternative utility measures.
Valuing Individual Health Outcomes: Objectives
Companion Slides. Teaching Pack: Valuing Individual Health Outcomes. Center for Health Decision Science, Harvard T.H. Chan School of Public Health 2017http://repository.chds.hsph.harvard.edu
• Video 1.1 Including intermediary outcomes (~12 min)
• Video 1.2 Using the standard gamble (SG) (~17 min)
• Video 1.3 Alternatives to the SG (~10 min)
• Video 2.1 Putting utilities into a tree (~4 min)
• Video 2.2 Utilities for different people (~5 min)
• Video 2.3 Different methods, different utilities (~7 min)
Video Outline
Companion Slides. Teaching Pack: Valuing Individual Health Outcomes. Center for Health Decision Science, Harvard T.H. Chan School of Public Health 2017http://repository.chds.hsph.harvard.edu
Video 1.1
Including intermediary outcomes:An example when facing a tough decision
after a motor vehicle accidentwith
Eve Wittenberg
Imagine a decision with three options for repair of a leg injury following a motor vehicle accident
Three options:
1. Experimental surgical repair
2. Surgical amputation
3. Do nothing
Companion Slides. Teaching Pack: Valuing Individual Health Outcomes. Center for Health Decision Science, Harvard T.H. Chan School of Public Health 2017http://repository.chds.hsph.harvard.edu
The goal is to allow for outcomes that are intermediate to survival (=1) and death (=0)
Companion Slides. Teaching Pack: Valuing Individual Health Outcomes. Center for Health Decision Science, Harvard T.H. Chan School of Public Health 2017http://repository.chds.hsph.harvard.edu
“An economic theory that describes how people make decisions when faced with an uncertain set of outcomes”
Expected Utility Theory
Companion Slides. Teaching Pack: Valuing Individual Health Outcomes. Center for Health Decision Science, Harvard T.H. Chan School of Public Health 2017http://repository.chds.hsph.harvard.edu
1. Completeness
2. Transitivity
3. Independence
4. Continuity
Axioms of Expected Utility Theory
Companion Slides. Teaching Pack: Valuing Individual Health Outcomes. Center for Health Decision Science, Harvard T.H. Chan School of Public Health 2017http://repository.chds.hsph.harvard.edu
1. Completeness: if 2 options exist, A&B, either A>B, B>A, or A=B
2. Transitivity
3. Independence
4. Continuity
Axioms of Expected Utility Theory
Companion Slides. Teaching Pack: Valuing Individual Health Outcomes. Center for Health Decision Science, Harvard T.H. Chan School of Public Health 2017http://repository.chds.hsph.harvard.edu
1. Completeness: if 2 options exist, A & B, either A>B, B>A, or A=B
2. Transitivity: If 3 options exist, A, B, & C, if A>B and B>C then A>C
3. Independence
4. Continuity
Axioms of Expected Utility Theory
Companion Slides. Teaching Pack: Valuing Individual Health Outcomes. Center for Health Decision Science, Harvard T.H. Chan School of Public Health 2017http://repository.chds.hsph.harvard.edu
1. Completeness: if 2 options exist, A & B, either A>B, B>A, or A=B
2. Transitivity: If 3 options exist, A, B, & C, if A>B and B>C then A>C
3. Independence: If more than 3 options exist, A, B, C, and others, if A>C then another alternative such as E, F, or G does not change A>C preference
4. Continuity
Axioms of Expected Utility Theory
Companion Slides. Teaching Pack: Valuing Individual Health Outcomes. Center for Health Decision Science, Harvard T.H. Chan School of Public Health 2017http://repository.chds.hsph.harvard.edu
1. Completeness: if 2 options exist, A & B, either A>B, B>A, or A=B
2. Transitivity: If 3 options exist, A, B, & C, if A>B and B>C then A>C
3. Independence: If more than 3 options exist, A, B, C, and others, if A>C then another alternative such as E, F, or G does not change A>C preference.
4. Continuity: if A>B>C, then there exists a lottery between A & C such that a person is indifferent between B for certain and an A/C lottery
Axioms of Expected Utility Theory
Companion Slides. Teaching Pack: Valuing Individual Health Outcomes. Center for Health Decision Science, Harvard T.H. Chan School of Public Health 2017http://repository.chds.hsph.harvard.edu
Continuity axiom
Companion Slides. Teaching Pack: Valuing Individual Health Outcomes. Center for Health Decision Science, Harvard T.H. Chan School of Public Health 2017http://repository.chds.hsph.harvard.edu
Video 1.2
Using the standard gamble (SG)with
Eve Wittenberg
• 0 = being dead
• 1 = perfect health, best imaginable health
Utility scale
Companion Slides. Teaching Pack: Valuing Individual Health Outcomes. Center for Health Decision Science, Harvard T.H. Chan School of Public Health 2017http://repository.chds.hsph.harvard.edu
How to value states between dead and perfect health: “intermediate states”?
“Standard gamble”
Certain outcome = intermediate state(a) Survive, prosthetic leg”(b) Survive, not able to walk and in pain
Gamble, or “lottery” is between dead (=0) and perfect health– fully functional leg (=1.0)
Companion Slides. Teaching Pack: Valuing Individual Health Outcomes. Center for Health Decision Science, Harvard T.H. Chan School of Public Health 2017http://repository.chds.hsph.harvard.edu
Standard gamble for “survive, prosthetic leg”: “Flo”
FLO
Is indifferent between certain state of prosthetic leg and gamble where probability of fully functional leg = 0.7 and dead =1.0-0.7=0.3
EV of gamble = 0.7
So utility of prosthetic leg = EV of gamble = 0.7
Companion Slides. Teaching Pack: Valuing Individual Health Outcomes. Center for Health Decision Science, Harvard T.H. Chan School of Public Health 2017http://repository.chds.hsph.harvard.edu
Standard gamble for “survive, not able to walk and in pain”: “Flo”
FLO
Is indifferent between certain state of survive, not being able to walk and in pain and gamble where probability of fully functional leg = 0.4 and dead =1.0-0.4=0.6
EV of gamble = 0.4
So utility of not being able to walk and in pain = EV of gamble = 0.4
Companion Slides. Teaching Pack: Valuing Individual Health Outcomes. Center for Health Decision Science, Harvard T.H. Chan School of Public Health 2017http://repository.chds.hsph.harvard.edu
Putting utilities back into decision tree
Companion Slides. Teaching Pack: Valuing Individual Health Outcomes. Center for Health Decision Science, Harvard T.H. Chan School of Public Health 2017http://repository.chds.hsph.harvard.edu
Averaging out and folding back tree
EV of experimental surgical repair branch = 0.8EV of surgical amputation branch = 0.686Value of no surgery branch = 0.4
So optimal choice for Flo is experimental surgical repair.
Companion Slides. Teaching Pack: Valuing Individual Health Outcomes. Center for Health Decision Science, Harvard T.H. Chan School of Public Health 2017http://repository.chds.hsph.harvard.edu
Video 1.3
Alternatives to the SGwith
Eve Wittenberg
Time trade-off (TTO): 10 years in intermediate health state = ? years in perfect health
Companion Slides. Teaching Pack: Valuing Individual Health Outcomes. Center for Health Decision Science, Harvard T.H. Chan School of Public Health 2017http://repository.chds.hsph.harvard.edu
TTO for prosthetic leg
6 years in perfect health = 10 years with prosthetic leg
TTO “utility” for prosthetic leg = 0.6
Companion Slides. Teaching Pack: Valuing Individual Health Outcomes. Center for Health Decision Science, Harvard T.H. Chan School of Public Health 2017http://repository.chds.hsph.harvard.edu
Visual Analog Scale (VAS)
NOT a utility
0-100 scale
“Where on line would you place your health?”
Companion Slides. Teaching Pack: Valuing Individual Health Outcomes. Center for Health Decision Science, Harvard T.H. Chan School of Public Health 2017http://repository.chds.hsph.harvard.edu
Video 2.1
Putting utilities into a treewith
Eve Wittenberg
Standard gamble can replace an intermediate state at end of tree branch
The break-even “gamble” or “lottery”—at the point of indifference with the intermediate health state--can replace that intermediate state returning the tree to one in which all outcomes are in terms of survival or death, 1 or 0.
Companion Slides. Teaching Pack: Valuing Individual Health Outcomes. Center for Health Decision Science, Harvard T.H. Chan School of Public Health 2017http://repository.chds.hsph.harvard.edu
Video 2.2
Utilities for different peoplewith
Eve Wittenberg
Different individuals may have different utility for the same health state
Utilities are subjective preferences, so may differ across individuals.
Flo places greater value on ambulation because she is a professional athlete. As a result, her utility for states with compromised mobility is LOWER than Maya’s (a writer by profession). Maya is also a mother of two, which may influence her willingness to trade any risk of death for improved health (as is the premise of the SG).
Companion Slides. Teaching Pack: Valuing Individual Health Outcomes. Center for Health Decision Science, Harvard T.H. Chan School of Public Health 2017http://repository.chds.hsph.harvard.edu
Video 2.3
Different methods, different utilitieswith
Eve Wittenberg
1. Standard gamble• Involves a trade-off• Interval scale• Incorporates uncertainty
2. Time trade-off• Involves a trade-off• Interval scale• No uncertainty
3. Visual analog scale• No trade-off• Ordinal, not interval scale• No uncertainty
Characteristics of methods
Companion Slides. Teaching Pack: Valuing Individual Health Outcomes. Center for Health Decision Science, Harvard T.H. Chan School of Public Health 2017http://repository.chds.hsph.harvard.edu
Created by the Center for Health Decision ScienceHarvard T.H. Chan School of Public Health
All materials produced by the Center for Health Decision Science are free and publicly accessible for educational use
chds.hsph.harvard.edu
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