Transcript Measurement & Valuation of Health

Measurement & Valuation of Health
 What is ‘health’?
 Why do we need to measure it?
 How can it be measured?
 Why do we need to value it?
 How can it be valued?
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What is health?
 Good health is…not bad health
• ‘Absence of disease’
 Good health is…a positive thing
• ‘Total physical and mental well-being’
 Good health is…two-dimensional
• ‘A long life and a happy life’
 Good health is…multidimensional
• ‘A long life plus an ability to do all the things that one wants to do’
 Good health is a …subjective concept
•
‘What makes me happy is not the same thing that makes you happy’
• ‘What made me happy yesterday is not the same thing that makes me happy today
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Why measure health?
 ‘Health’ is the ‘product’ of health care
• not ops performed, no patients treated etc
 Clinical reasons - effectiveness
 Economic reasons - efficiency
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 Length of life
• Mortality (numbers, rates, SMRs)
• Life expectancy
• Life years lost
 Quality of life
• Numerous QoL measures (generic and specific)
• SF-36, Nottingham Health Profile, Guttman Scale, Rotterdam
Symptom Checklist, Hospital anxiety and depression scale etc….
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Limitations of measurements/need for valuation
 Confines response to questions posed - may not
incorporate all relevant aspects of health
 Multitude of instruments - compatibility?
 Ambiguity in assessing overall improvement of
detriment in health
 Efficiency - value of benefits > value (opp) cost
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Valuation versus Measurement
 Value is determined by benefits sacrificed
elsewhere
 Valuation requires wade-off benefits
• measurement does not
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Methods of valuing health
 ‘Utility or prefoeuce assessment eg QALYS
 Monetary terms eg WTP
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QUALITY ADJUSTED LIFE YEARS
(QALYS)
Adjusts data on quantity of life years saved to reflect a
valuation of the quality of those years
If healthy:
QALY = 1
If unhealthy:
QALY < 2
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QL Weighting
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QALY PROCEDURE
 Identify possible health states - cover all important
and relevant dimensions of QoL
 Derive ‘weights’ for each state
 Multiply life years (spent in each state) by ‘weight’ for
that state
HEA PTP: M207 Health Economics
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“UTILITY” WEIGHT
Utility = satisfaction/well-being - reflects a consumers
preferences
Utility weights are necessarily subjective - they elicit
an individual’s preferences for, or value of, one or
more health states.
Must:
1.
2.
Have interval properties
Be ‘anchored’ at death and
‘good health’
HEA PTP: M207 Health Economics
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TECHNIQUES FOR MEASURING
“UTILITY”
Variety of techniques available, including:
 Time Trade off
 Person Trade Off
 Standard Gamble
 Magnitude Estimation
 Rating Scale
HEA PTP: M207 Health Economics
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OBTAINING “UTILITY” WEIGHTS
Two means of obtaining “utility” weights:
1.
Evaluation specific/’holistic’ measures - develop evaluation
specific (‘holistic’) description of health state and then
derive weight for that specific state directly by population
survey
2.
Use ‘generic’ or ‘multi-attribute’ instruments - use
predetermined weights, based on combination of
dimensions of health yeilding a finite number of health
states/values
HEA PTP: M207 Health Economics
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EVALUATION SPECIFIC/’HOLISTIC’
MEASURE
Advantages:
Disadvantages
1.
Sensitive
2.
Account for wider QoL factors
(eg process utility, duration/prognosis)
1.
Cost and time intensive
2.
Lack of comparability
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GENERIC (MAU) INSTRUMENTS
Advantage:
1.
Supply weights “off the shelf”
Disadvantages:
1.
Insensitive to small changes in
health
Dimensions may not be
sufficiently comprehensive
Weights may not be
transferable across groups
2.
3.
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SOME OTHER ISSUES
 Choosing respondents for utility estimation - whose values
count
 What constitutes a ‘correct’ health state description?
 What is the appropriate ‘measurement’ technique?
 Aggregation of values?
 Biases - against, life enhancing versus life-saving etc.
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Why Monetary Valuation?
 Assessment of allocative efficiency ie positive Net
Present Value (NPV)
 Valuation of non-health benefits eg process,
information, convenience
 Valuation of non-use benefits ie externalivies, orphan
value
HEA PTP: M207 Health Economics
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Methods of Monetary Valuation
 Court awards (death/injury)
 Political process/implicit public sector awards
 Life insurance
 ‘Human capital - value of production
 Observed wealth - risk trade-off
 Direct survey
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Human Capital Approach
Benefits
=
gains in productive output
(due to ill health)
Valuation Basis
=
earnings / wage data
Issues
=
discriminatory
value based on researcher
not value based on economic
theory
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‘Willingness to Pay’ Approach
Benefits
=
what someone is willing to
give up (pay) to have the
commodity
Valuation basis
=
money represents a claim
on benefits from consumption
of other commodities
=
individual preference
HEA PTP: M207 Health Economics
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Means of Estimating WTP
“Im p licit”
or
“R e ve a le d ”
p re fe re n ce
“C o n tin g e n t”
o r “S u rve y”
va lu a tio n
HEA PTP: M207 Health Economics
A d va n ta g e s
D isa d va n ta g e s
R e a l p re fe re n c e s
D ifficu lt to iso la te
va lu e o f b e n e fit
co n fo u n d e rs
D ire ct va lu a tio n o f H yp o th e tica l
b e n e fit o f g o o d
m a rke t “S u rve y
p ro b le m s ”
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