Decision Analysis 101

1. Decision Analysis 101Decision Analysis 101
Stefan Tigges MD MSCRStefan Tigges MD MSCR

2. What is Decision Analysis?What is Decision Analysis?
 Best course of action underBest course of action under
conditions of uncertaintyconditions of uncertainty
 Rationalize decision makingRationalize decision making
 Basic conceptsBasic concepts
 Expected valueExpected value
 Decision trees/IngredientsDecision trees/Ingredients
 ExamplesExamples
 Audience participationAudience participation

3. Key Concept: Expected ValueKey Concept: Expected Value
 Average payoff ofAverage payoff of
random trialrandom trial  P x VP x V
 P(outcome)P(outcome)
 Outcome valueOutcome value
 Expected value mayExpected value may
not be a possiblenot be a possible
outcomeoutcome
 Gambling exampleGambling example

4. Should I Buy a Ticket?Should I Buy a Ticket?
 Wikipedia: California Lottery Mega MillionsWikipedia: California Lottery Mega Millions
 Minimum payoff is $12,000,000Minimum payoff is $12,000,000
 P(Winning) is 1/175,711,536P(Winning) is 1/175,711,536
 Cost is one dollarCost is one dollar

5. Should I Buy a Ticket?Should I Buy a Ticket?

6. Types of Expected ValuesTypes of Expected Values
 Expected ValueExpected Value
 P(outcome)P(outcome)
 Value of outcomeValue of outcome
 DollarsDollars
 Years of survivalYears of survival
 UtilityUtility
 QALYQALY

7. Outcome: UtilityOutcome: Utility  DesirabilityDesirability
of a Health Stateof a Health State
Expected Value= P(outcome) x ValueExpected Value= P(outcome) x Value

8. Outcome: Treatment UtilityOutcome: Treatment Utility

9. Decision Analysis IngredientsDecision Analysis Ingredients
 Comparing expectedComparing expected
values of differentvalues of different
options, X vs Yoptions, X vs Y
 Decision treeDecision tree
 OutcomesOutcomes
 ProbabilitiesProbabilities
Expected Value= P(outcome) x ValueExpected Value= P(outcome) x Value

10. Decision Tree BasicsDecision Tree Basics
TimeTime
DecisionDecision
OptionsOptionsOutcomesOutcomes

11. Decision Tree BasicsDecision Tree Basics

12. Decision Tree BasicsDecision Tree Basics

13. Example: R/O CADExample: R/O CAD

14. First Make a ChoiceFirst Make a Choice

15. PossibilitiesPossibilities

16. More PossibilitiesMore Possibilities

17. Final TreeFinal Tree

18. And the Winner is…And the Winner is…

19. Shortcomings of Decision AnalysisShortcomings of Decision Analysis
 Risk AverseRisk Averse
 QALY (Y x U)QALY (Y x U)
 Years survivalYears survival
 UtilityUtility
 SubjectiveSubjective
 Doctor/patient/familyDoctor/patient/family
 Other NumbersOther Numbers
 LiteratureLiterature
 UncertaintyUncertainty
 Test accuracyTest accuracy
 CostsCosts

20. Sensitivity AnalysisSensitivity Analysis
 Technique that recognizes range of valuesTechnique that recognizes range of values
 ProbabilitiesProbabilities
 OutcomesOutcomes
 TypesTypes
 One-WayOne-Way
 Two-WayTwo-Way
 Three-WayThree-Way

21. Tornado DiagramTornado Diagram

22. Sensitivity Analysis: Prob CadSensitivity Analysis: Prob Cad

23. One Way Sensitivity AnalysisOne Way Sensitivity Analysis
Range
.05 to .95

24. Tornado DiagramTornado Diagram

25. Sensitivity Analysis: Cath MortalitySensitivity Analysis: Cath Mortality

26. One Way Sensitivity AnalysisOne Way Sensitivity Analysis
Range
.000001 to .1

27. Two Way Sensitivity AnalysisTwo Way Sensitivity Analysis
Range Cath
Mortality
.000001 to .1
Range CAD
Probability
.05 to .95

28. Three Way Sensitivity AnalysisThree Way Sensitivity Analysis
Sensitivity Analysis on
Mortality of Cath and Sensitivity of Cath and Sensitivity of CT
Mortality of Cath
SensitivityofCath
0.00 0.03 0.05 0.08 0.10
0.990
0.943
0.895
0.848
0.800
Cardiac CT
Coronary Cath
Sensitivity of CT = 0.800
Sensitivity Analysis on
Mortality of Cath and Sensitivity of Cath and Sensitivity of CT
Mortality of Cath
SensitivityofCath
0.00 0.03 0.05 0.08 0.10
0.990
0.943
0.895
0.848
0.800
Cardiac CT
Coronary Cath
Sensitivity of CT = 0.848
Sensitivity Analysis on
Mortality of Cath and Sensitivity of Cath and Sensitivity of CT
Mortality of Cath
SensitivityofCath
0.00 0.03 0.05 0.08 0.10
0.990
0.943
0.895
0.848
0.800
Cardiac CT
Coronary Cath
Sensitivity of CT = 0.895
Sensitivity Analysis on
Mortality of Cath and Sensitivity of Cath and Sensitivity of CT
Mortality of Cath
SensitivityofCath
0.00 0.03 0.05 0.08 0.10
0.990
0.943
0.895
0.848
0.800
Cardiac CT
Coronary Cath
Sensitivity of CT = 0.943

29. Three Way Sensitivity AnalysisThree Way Sensitivity Analysis

30. Do it Yourself Decision AnalysisDo it Yourself Decision Analysis
 Problem: You chooseProblem: You choose
 IngredientsIngredients
 Decision tree: time flows left to rightDecision tree: time flows left to right
 ChoicesChoices
 OutcomesOutcomes
 ProbabilitiesProbabilities
 ValuesValues