Measurement & Valuation of Health
Download
Report
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?
HEA PTP: M207 Health Economics
1
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
HEA PTP: M207 Health Economics
2
Why measure health?
‘Health’ is the ‘product’ of health care
• not ops performed, no patients treated etc
Clinical reasons - effectiveness
Economic reasons - efficiency
HEA PTP: M207 Health Economics
3
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….
HEA PTP: M207 Health Economics
4
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
HEA PTP: M207 Health Economics
5
Valuation versus Measurement
Value is determined by benefits sacrificed
elsewhere
Valuation requires wade-off benefits
• measurement does not
HEA PTP: M207 Health Economics
6
Methods of valuing health
‘Utility or prefoeuce assessment eg QALYS
Monetary terms eg WTP
HEA PTP: M207 Health Economics
7
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
HEA PTP: M207 Health Economics
8
QL Weighting
HEA PTP: M207 Health Economics
9
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
10
“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
11
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
12
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
13
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
HEA PTP: M207 Health Economics
14
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.
HEA PTP: M207 Health Economics
15
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.
HEA PTP: M207 Health Economics
16
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
17
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
HEA PTP: M207 Health Economics
18
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
HEA PTP: M207 Health Economics
19
‘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
20
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 ”
21