efficiency of health care systems 2013 what it is and how to measure and compare it_ gernot...
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Efficiency of Health Care Systems – what it is and how to measure and compare it
by Gernot Pehnelt
--DRAFT--
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Introduction
Health – often referred to as the „highest good‟ (summum bonum) – and the provision of
health care services have been a major issue in national and international politics and, not
least, for the very individual, indeed. The question on how effective, efficient and fair health
care systems around the globe perform has attracted much attention and an intensive and
controversial debate not only in academic and political circles. In recent years, quite a few
studies have been conducted in order to evaluate and compare the efficiency of health care
systems. Given the different theoretical and methodological approaches, it is rather
unsurprising that the results of these studies are far from conclusive.
In this study, we will discuss the question what efficiency of health care systems actually
means, how it can be measured and – finally – how the performance of health care systems
can be compared on a reasonable and fair basis. In order to do so, we will first develop a
theoretical framework of the very nature of the „production process‟ of health care systems.
Based on these theoretical considerations, various approaches to evaluate the performance of
health care systems will be assessed and a procedure to measure the efficiency of different
health care systems will be developed and discussed.
The Health Care System – A Productive Entity
The Output Dimension
According to the World Health Report 2000 (WHO 2000) health systems are defined as
comprising all the organizations, institutions and resources that are devoted to producing
health actions. A health action is defined as any effort, whether in personal health care, public
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health services or through intersectoral initiatives, whose primary purpose is to promote,
restore or maintain health. In other words, health care systems can be described as productive
entities, consisting of various components or sub-divisions, whose primary goal and –
economically speaking – output is the improvement of the health care status of the (potential)
patients.1 The value of healthy time gained by health actions can manifest itself in various
forms. Healthy time can be used for productive work generating income for the very
individual and creating an output and additional wealth for the society. Healthy time could
also be used for leisure activities yielding to additional perceived personal utility. Last but not
least, living in a better health state has a value to the individual in its own right, e.g. the
absence of pain, higher mobility and better quality of life (Drummond et al. 2005).
Sure, there are various other goals that contribute to the performance of a health care system
including accessibility, fairness, a sustainable and just financing, customer satisfaction,
transparency, respect for the patient etc. However, these instrumental goals are rather means
to the very end of health care „production‟ which is protecting and improving the health status
of the entire population over people‟s whole life cycle. Once the achievement of this final
goal can be measured, there might be no reason to integrate every single outcome or sub-
ordinate target explicitly into the efficiency analysis. Unfortunately, the improvement of the
health status of the patients due to health actions cannot be measured directly. This is, first,
because there is no exact measure or even a good proxy of the (virtual) health status of the
population in the absence of any health care system.2 Second, the actual health status of any
individual within a society with all the relevant physical and mental dimensions3 can hardly be
quantified at a certain point in time, let alone in a dynamic perspective. Third, as we will
discuss later, there are many factors outside the health care system that might influence the
health status of individuals. To sum up, many questions about health system performance
have no clear or simple answers because outcomes are hard to measure and it is hard to
disentangle the health system‟s contribution from other factors (WHO 2000).
Different outcome measures have been used to approximate the performance of health care
systems. Generic outcome measures often used in utility analysis are quality-adjusted life-
years (QALYs)4, healthy-years equivalent (HYE)5, the disability-adjusted life-years (DALY)6,
1 The term „potential patients‟ basically includes the entire population of a country since every individual has
a certain demand for health services, let it be in cases of urgent emergencies, a demand for general
diagnostic procedures, basic services or some sort of optional demand. 2 Even very simple and indigenous societies have some sort of a health care system and use resources to
perform health actions. 3 By the way, following the definition of health given by the World Health Organization (WHO) whereby,
“health is a state of complete physical, mental and social well-being and not merely the absence of disease
or infirmity”, almost every human being might “suffer” from certain health deficits. 4 QALYs basically take into account the quality and the quantity of the life years added by a medical
intervention. Each year in perfect health is assigned the value of 1 down to a value of 0 for death. If the extra
years were not being lived in full health, for example if the patient suffers constant pain or be confined to a
wheelchair, then the extra life-years would be weighted with a value between 0 and 1 to account for this. 5 HYE is calculated o the basis of the number of years of perfect health that has the same utility as the lifetime
path of health states under consideration (Gold et al. 1996). 6 The DALY is a health gap measure that extends the concept of potential years of life lost due to premature
death to include equivalent years of “healthy” life lost by virtue of being in states of poor health or disability.
It combines in one measure the time lived with disability and the time lost due to premature mortality. One
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age specific mortality rates, infant mortality or simply the life expectancy at birth. On the one
hand, these indicators are appropriate proxies for the final outcome of a health care system
and other factors that influence the health status of human beings. On the other hand, the
output of health care systems is multidimensional, by all means. First, because of the massive
technological progress and accumulation of knowledge about the factors that influence the
health status, certain diseases and their transmission, etc. the scope of modern health care
systems is much more diversified than a couple of decades before. Health education, for
instance, becomes more and more important when it comes to combating some of the most
widespread diseases in Western society, such as obesity and diabetes. Second, people do no
longer occupy the health care system for just the relief of pain and treatment of physical
limitations and emotional disorders. They are also looking for diagnostic procedures on a
regular basis without a direct indication, for advice on diet, child-rearing and other behaviour.
Third, maintaining and improving a functioning health care system with sufficient capacities,
decent facilities and well educated experts meets a certain optional demand that every
individual has. That is why offering state-of-the-art health care services or providing the
opportunity to use health care resources is an output itself. 7 Fourth, product and process
innovation and technical progress in diagnostics, surgery, medication etc. also contribute to
the performance of health care systems. The higher the rate of technological progress and
accumulation of knowledge, the more effective will be the identification of disease patterns
and, finally, the treatment of patients. Furthermore, under certain (unfortunate) circumstances,
such as a natural disaster or a high prevalence of certain diseases (diabetes, HIV/Aids etc.)
because of the population‟s genetic exposure or life-style patterns the health care system of a
particular country might have to carry out a lot of health actions in order to maintain a decent
level of health amongst the population whereas the health care system of another country
simply does not face these rather structural problems that cannot be influenced in the short run.
Saying this, it has to be recognized that to perform health actions is an (intermediate) output
itself. Overall, there might be a case for integrating some of these additional or intermediate
outputs when it comes to the assessment of the performance of health care systems.
The Input Dimension
In order to assess the productivity of health care system, one has to define the actual
boundaries of a health system regarding the very inputs that are used to „produce‟ the
multidimensional output. There have been quite a few attempts to define boundaries that
separate the health system from elements outside of it (e.g. Terris 1978, Hsiao 1992,
Chernichovsky 1995). There is little doubt about that certain facilities and services such as
hospitals and primary care are elementary parts of the input domain of health care systems.
There is more controversy around components that have health-enhancing benefits but are not
DALY can be thought of as one lost year of „healthy‟ life and the burden of disease as a measurement of the
gap between current health status and an ideal situation where everyone lives into old age free of disease and
disability (WHO 2008). 7 One important objective of modern health systems is to respond to people‟s expectations regarding not only
the actual quantity and quality of care but also the availability of decent treatment – just in case.
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primarily intended to influence the overall level of health within a society.8 Examples for such
factors are the educational system or urban infrastructure. Furthermore, there are some
regulations and actions that clearly aim at the safety or health of individuals but are still not
referred to as inputs within the health care system. For example, the prohibition of smoking in
public buildings does most probably influence the smoking habits of individuals and – most
definitely – contribute to the health of non-smokers who work in public buildings. However,
the costs that are related to the enforcement of non-smoking rules are usually not integrated as
an input of the production process of health care systems. The same holds for environmental
and labour standards, certain safety rules and other regulations. One could argue that health
education at school is primarily intended to promote health and should therefore be
recognized in productivity analyses. Well, looking straight forward at first glance, this issue is
– again – far from trivial. First, the question is whether deeper understanding of how diseases
are spread, how important individual hygienic practices and a decent nutrition are and how
certain habits may influence the risk of getting ill is an input or an output of health care
system. On the one hand, the resources used to teach the students these things are means to an
intended end; that is improved health. Therefore, these resources can be referred to as inputs
in the production process of the health system. On the other hand, enhancing people‟s
knowledge about health related issues and giving them the opportunity to choose their
individual life-style and habits rationally on the basis of a well-founded cognition of the
complex sphere of health is most definitely beneficial and therefore an output itself. Second,
from a practical point of view, one must confess that it would be almost impossible to
separate the resources that have been used primarily in order to – directly or indirectly –
promote health, let it be in public schools, businesses or sports clubs. How many hours a year
does the 2nd
grade teacher at school spend to teach things that are primarily intended to
promote children‟s health or their knowledge about health related issues? How many
resources does a medium-sized enterprise invest to maintain or improve the health of its
employees and what will be the result? Even if some schools or businesses account for these
things, comprehensive information about these health-related inputs/outputs do not exist on a
broader scale and will most probably never exist.
Each health system should be judged according to the resources actually at its disposal, not
according to other resources which in principle could have been devoted to health but were
used for something else (WHO 2000), even if these activities outside the health care system
do have an impact on the health status of the population. We call factors that are outside the
defined boundaries of the health care system non-health care determinants. To make one thing
clear, these non-health care determinants may play a major role in assessing the overall
performance of health care systems and are of special importance in explaining differences
between countries. That is why they surely have to be recognized in any analysis, though
maybe not explicitly as direct inputs in the very production process of health care systems.
However, given the considerations discussed above, we prefer a rather narrow definition of
the boundaries of health care systems. It is the resources that are employed in the health care
8 “Clearly, all boundary definitions are arbitrary but to undertake an assessment of health system performance
an operational boundary must be proposed.” (Murray and Frenk 1999)
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sector and, indeed, health care expenditures that matter most when it comes to an assessment
of the efficiency of health care systems. Some of the resources used in the production process
in the narrower sense can be measured relatively easily. It is the labour employed in the health
sector, the capital that has been invested in health care facilities, the utilities and other health
care expenses that can be measured in monetary terms. However, there are still some
important inputs that are rather intangible, such as the specific know-how and the level of
technology. These inputs can be estimated by certain proxies as the number of high-tech
equipment such as MRT or CT or the ratio of examined medical personnel employed in the
health care sector.
The health care production process at a glance
The production process of health care systems can be described as follows. Resources that lie
within the boundaries, referred to as health care resources, are used to provide health care
services in order to improve the health status of the population.9 The primary output of this
process is the difference between the initial health status of the population (without any health
services) and the actual health status that has been achieved due to the health actions
performed by the health system (the “delta” in Figure 1).
Figure 1: The health care system as a productive entity
The initial (and actual) health status of the population as well as the health care system itself
are highly influenced by factors that lie more or less outside the boundaries of the health care
systems, such as the average income, the educational level, sanitation and nutrition, the
9 The patients are the most important physical input of the production process, so to speak.
population (potential patients)
initial health status
non-health care determinants:
average income
education
sanitation, nutrition
environment, polution etc.
life-style
other socioeconomic factors
health care system
health care resources
regulation and other policies
population
actual health status
∆ =
ou
tpu
t o
f th
e h
ealt
h c
are
sys
tem
6
environment, genetic exposure, the life-style and other socioeconomic factors.10 These non-
health care determinants might be even more important for the health status of a country‟s
population. In fact, some evidence suggests that health systems make little or even no
difference regarding the overall level of health. Comparisons across countries show that while
per capita income, education, income inequality or cultural characteristics are strongly related
to the actual health status there seems to be little independent connection between the level of
health and health care inputs such as doctors or hospital beds (Cochrane et al. 1978), total
health expenditure (Musgrove 1996), expenditure only on conditions amenable to medical
care (Mackenbach 1991), or public spending on health (Filmer and Pritchett 1999). It is not
surprising to find that these relations are weak in rich countries, since many causes of death
and disability are already controlled and there are many different ways to spend health system
resources, with quite varying effects on health status. But health system expenditure often
seems to make little difference even in poor countries with high infant and child mortality,
which should be a priority to reduce (WHO 2000).11
Figure 2 translates the complex health care system into terms of production. The initial
(secondary) inputs such as medical personnel and other labour, equipment, facilities and other
capital, know-how, utilities and other resources are used and combined in the production
process. The very nature of this production process in terms of a production function remains
pretty much unclear and can be referred to as a “black box”. The intermediate output of this
production process are the health actions that are performed to reach the final goal. These
secondary outputs such as diagnoses, surgeries and other procedures, outpatient treatments
and care days, medication, information and documentation are used as primary inputs in order
to cure the patients, ease their pain, weaken the symptoms and maintain or improve overall
health which is the final and primary output of the health care system.
10 Maybe, some of these factors can be influenced by certain health policies and regulations, at least in the long
run. However, many of these non-health care determinants lie completely outside even a broad definition of
what health systems are. 11 There is little evidence for a significant impact of higher cost on beneficiary outcome. Some regions in the
US have markedly higher cost than others, with no higher patient satisfaction or health improvement
(Dartmouth 1998).
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Figure 2: Inputs and outputs in the health care production process
As discussed before, the secondary inputs can be measured relatively easily by counting the
number employees or the full-time equivalents (FTE) in the different sub-sectors of the health
care system and collecting data about health care expenses. The same is true for the secondary
outputs that are basically well documented in health care statistics. The difficult part is to
quantify the primary output. The generic measures or a combination of some of these
measures mentioned above seem to be the most appropriate way to estimate the final outcome
of the production process.
The assessment of health system performance
The concept of relative performance
Given the tremendous importance of non-health care determinants for the initial and actual
health status of the population, international comparisons of the performance of health care
systems are not a trivial task. Just comparing the outcome or output-input-ratios might be not
appropriate to get a reasonable and fair assessment of the overall performance and efficiency
of different health systems around the world. In the following we explain the difficulties that
come around and develop an approach that is able to overcome some of these problems.
Murray and Frenk (1999) introduced a concept that compares the actual performance of a
health care system with its potential, taking into account that the actual outcome – that is the
health status of the population – would not be zero if there was no health care system at all.
Even without any health care expenditure or a functioning health care system, health levels
process 1 process 2
process n
production process („Black Box")
(combination of secondary inputs)
• capital
• labour
• know-how
• utilities
• other resources
• diagnose
• procedures and
surgeries
• patient & care days
• medication
• documentation
• cure
• easing the pain
• weakening the
symptoms
• improve overall health
health care resources
/ secondary inputs
primary input /
secondary
output
primary output
…
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would not be zero because the entire population would not be dead or seriously ill. The initial
health status, so to speak, of a country‟s population is supposed to be highly correlated with
various factors such as the average income, the educational level, environmental issues,
infrastructure, sanitation, nutrition and the like (non-health care determinants). The outcome
of a health care system could be defined as the difference between the observed health status
of the entire population and the initial (virtual) health status of the population given a certain
level of these factors. Therefore, performance of the health system involves relating goal
attainment to what could be achieved under certain circumstances that cannot be addressed by
the health care system directly. In other words, performance is a relative concept. A rich
country has higher levels of health than a poor one, but which country has a higher level of
performance relative to health system resources? Murray and Frenk (1999) argue that
performance should be assessed relative to the worst and best that can be achieved for a given
set of circumstances.
Figure 3 illustrates an example.12 The upper lines (hmaxi) show the maximum attainable level of
health (y-axis) for the given level of health expenditures (x-axis), given the non-health care
determinants of health status such as the average income, the educational level or
environmental pollution for every country i. The stars (hmini) represent the minimum level of
health given the specific non-health system circumstances in this particular country i. The
circles (Hi) show the actual observed health status in each country i. What can be seen is that
country A certainly has a lower level of health than country B – initially (hminA < hmin
B) and
actually (HA < H
B). However, both countries show exactly the same health care system
performance in absolute terms, no matter if this performance is measured by the distance
between minimum level and the actual level of health (p* = improvement due to the health
care system) or the distance from the observed health status to the maximum attainable
frontier (p° = potential improvement / level of inefficiency). In relative terms, the
performance of country A‟s health care system is even better than the performance of B.
Notice that even if country A invested as much health care resources as country B, the initial
health status of country A‟s population would still quite below the health status of country B‟s
population (hminA < hmin
B). That is due to unfavourable circumstances such as certain
socioeconomic, life-style or environmental factors. That is why the maximum attainable
health status – the individual efficient frontier – at a given amount of health expenditures is
also lower in country A than in country B (FhmaxA < Fhmax
B). 13
12 The examples and illustration given by Murray and Frenk (1999) and elsewhere (e.g. Evans et al. 2001) are
somehow misleading. That is why we use a different approach to illustrate the very problem. 13 The shape of the efficient frontier implicitly assumes diminishing marginal returns to investments in health
care services. We will discuss this issue later in this chapter. The slope of the minimum level of health
(Fhmin) can be expected to have a curved slope as well. However, since this detail is not relevant here, we
skip this discussion.
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Figure 3: Health system performance
There might be another country (C) that has the same actual health status as country B (HC =
HB). At first glance, country C would probably ranked first among the three countries if it
comes to a simple ratio analysis of the performance of the health care system since country C
uses fewer resources than country B and reaches the same overall health status. However, the
performance of country C‟s health care system seems to be not much better or even weaker
than B‟s performance, since the improvement due to the health care system is lower in
country C than in country B (p*C < p
*B) and the lack of efficiency compared to the individual
efficient frontier (Fhmax) is higher in country C (p°C > p°
B). Because of the favourable non-
health care determinants of health status in country C, this country could reach a much higher
overall health status than it does (see the efficient frontier FhmaxC). C faces the highest
individual efficient frontier among the three countries.
To assess the relative performance of health care systems, it would be desirable to develop an
individual benchmark, an upper limit or “frontier”, corresponding to the best practice that
could be achieved by the health system under consideration. This frontier would represent the
level of attainment which a health system might achieve under the given non-health care
determinants, but which no country surpasses (Donabedian et al. 1982). With such a frontier
approach it would be possible to see how much of the potential has been realized. In other
words, comparing actual attainment with potential shows how far from the relevant frontier of
maximal performance is each country‟s health system (WHO 2000). In economic terms, the
distance between the actual outcome and the potential would be referred to as slack or
inefficiency.
Now we draw our attention to the slope of the best-practice frontiers in Figure 3 which leads
us to a very important fact that have not been recognized by the vast majority of empirical
studies. It is very reasonable to assume diminishing returns in the production of health
hmaxA
hmaxB
hmaxC
HB
HC
HA
p*C
hminA
hminB
hminC
Country C hea
lth s
tatu
s
health system resources
Country A
Country B
p*A
p*B p°
A
p°B p°
C
FhminA
FhminB
FhminC
FhmaxB
FhmaxA
FhmaxC
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concerning the final outcome, regardless the measure applied. Coming from a very poor level
of overall health, i.e. a low life-expectancy, it might take just a few relatively inexpensive
measures to improve the average health and life-expectancy of the population. The
improvement of hygiene in hospitals, for instance, has dramatically reduced hospital mortality
in the 20th
century. The cost of the related measures, such a sterilizing surgical instruments or
simply encouraging medical personnel to wash one‟s hands and provide the necessary
facilities to do so, are comparably low. The same holds for basic vaccination. Some diseases
have almost been wiped out in many industrialised countries in the last century due to
vaccination. By the way, some of the most effective measures that are able to enhance the
overall health status and improve the life-expectancy lie outside the health care system. The
tremendous increase in life-expectancy and the quality of life since the mid-1800s where due
to better nutrition, improvements in urban sanitation and personal hygiene that came along
with a better understanding of how diseases spread and, not least, the rise of capitalism, an
enhanced division of labour and the subsequent economic growth and increasing social
welfare. Technically speaking, economic growth pushed the frontiers upwards and increased
the overall level of health by improving the initial health status. Furthermore, technological
progress and a more efficient use of resources made it possible to invest more in health, which
would be represented by a country‟s move to the right in Figure 3.
Once a country has already reached a high level of health, it takes much more effort to further
reduce morbidity and increase life-expectancy. Compared to the rather basic health actions
mentioned above, the treatment of certain diseases like cancer are very expensive. Although
modern chemo and radiation therapy together with subsidiary medication are quite successful,
they are not able to increase the average life expectancy within the society by years or even
decades like some of the measures discussed above could. The same is true for almost every
intensive care measure. Intensive care, a surgery or decent medication can save one‟s life,
ease the pain or even cure a disease and therefore add some additional life-time. However, in
the end, even if one disease can be successfully defeated, it just means replacing one
particular cause of death by another one. The higher the average level of health (e.g. the life-
expectancy) is, the harder and more expensive it gets to further improve the health and life
expectancy of the population.
Why is this important for efficiency analyses of health care systems? Well, economically
speaking, the health system faces diminishing marginal returns – beyond a certain level, the
production function becomes very flat. That is why country B in Figure 3 has to invest much
more into its health care system (in absolute and relative terms) to get a marginal
improvement of the overall health status than country A. In other words, the marginal
productivity of country A‟s health care system at this certain point of economic development
is by nature higher than the marginal productivity of country B‟s health system. Any
investment in health actions in country A (movement to the right in Figure 3) would add quite
a lot to the average level of health in this country, whereas country B must invest quite a lot to
increase the overall health of its population just a bit. What can be drawn is that, because of
various reasons, it is a trivial task to actually compare the efficiency of country A and country
B regarding the production of health.
11
However, there have been attempts to compare the efficiency of different health care systems
and some of them are quite promising. Since some studies do not take the relative nature of
efficiency into account, we, in the following, rather focus on studies that do incorporate the
relative concept of performance.
Data Envelopment Analysis – an appropriate tool to measure relative efficiency
Based on the work of Farell (1957)14 Charnes et al. (1978) developed the Data Envelopment
Analysis (DEA) to measure the efficiency of productive entities, so called decision making
units (DMUs). This method, which has been advanced during the last decades 15, is very
appropriate in assessing the (relative) efficiency of DMUs that produce multidimensional
outputs and use certain inputs that cannot be measured in monetary terms.
Model (1) calculates the relative efficiency of DMU 0 in comparison to every other DMU in
the observed sample of n DMUs. Every DMU j is a productive entity that uses the i = 1,..., m
inputs (xij > 0) to produce r = 1,..., s outputs (yrj > 0). The model chooses the individual
weights of every single input and output (qi, pr) in a way that maximizes the efficiency score
ho.
m.,...,1is,...,1r0q ,p
n...,,1 j1
xq
yp
NB:
xq
yp
hmax
ir
m
1i
iji
s
1r
rjr
m
1i
oi
s
1r
ror
oq ,p
(1)
The optimization model (2) – the so called envelopment-form – calculates the DEA-Score θo*
that shows to which level the DMU 0 has to reduce the inputs x to become efficient. Efficient
units get a DEA-Score of 1.
n.,...,1j0λ
m,...,1i0xλθx
s,...,1ryyλNB:
θmin
j
n
1j
ijjio
ro
n
1j
rjj
oλ
(2)
14 For an overview on the origins of Data Envelopment Analysis see Forsund and Sarafoglou (2002). 15 See for instance Löthgren and Tambour (1996), Andersen and Petersen (1993), Cooper et al. (1996) and
Sengupa (1989). Seiford (1996) provides an outline of the early developments and a bibliography of the
DEA.
12
Figure 4 shows an example with seven DMUs that produce the same output (quantity and
quality) with two inputs.
Figure 4: DEA – Example with 7 DMUs, two inputs and one output
The efficient DMUs A, B, C, D and E lie on the frontier.16 The frontier “envelops” the two
inefficient DMUs F and G. In order to be ranked efficient, F and G had to reduce both inputs
to reach point C and G‟, respectively. As can be seen, the DEA is a relative concept of
efficiency. The efficiency of every DMU is assessed relatively to the performance of real
DMUs or convex combinations of existing DMUs. The benchmark, so to speak, for DMU F is
DMU C. The benchmark for DMU C is constituted by a combination of the efficient peers C
and D.
DEA explicitly incorporates the relative concept of efficiency by measuring the relative
distance of every DMU to the best-practice frontier. Furthermore, the peers or benchmarks of
every inefficient DMU are generally similar to that DMU in terms of the relative importance
of the inputs and outputs in the production process.
With DEA one can also take into account variable returns to scale. Some technologies possess
increasing returns to scale, whereas other production processes might come along with
constant or decreasing returns to scale. Under the assumption of constant returns to scale
(CRS), the efficient frontier FCRS in Figure 5 is determined by the position vector from the
origin through the points C and A. The efficient DMUs A and C lie on this frontier and are
identified as efficient (θACRS* = θC
CRS* = 1). The other DMUs (B, D and E) are ranked inefficient
by the CRS-model (θBCRS* , θD
CRS* , θECRS* < 1). The magnitude of the inefficiency is quantified by
the relative distance of the inefficient DMU to the frontier. In case of DMU B this is the ration
B°B‟‟/B°B. In order to become efficient, DMU B had to reduce the input by the distance BB‟‟.
16 The frontier is determined by linear sections (convex combinations) between two efficient DMUs at a time.
Note that DMUs A and E lie on the frontier although they could reduce one input by one unit. The DMUs A
and E exhibit some slack and are called “weakly efficient”.
Input 1
Input 2
A
B
C
D E
F
G
G’
1 2 3 4 5
1
2
4
3
0
13
Figure 5: DEA – CRS- and VRS-model
Under the assumption of variable returns to scale (VRS) the best-practice frontier FVRS is
determined by the DMUs A, B, C and D and the respective convex combinations of the
neighbouring DMUs. The VRS-model identifies 4 of the 5 DMUs as efficient, taking into
account that up to a certain size, the production process possesses increasing returns to scale
and beyond a certain threshold decreasing returns to scale. In other words, the DMUs B and D
produce technically efficient but are too small (DMU B) or too large (DMU D) to be fully
efficient. DMUs B and D are scale inefficient. The magnitude of the scale inefficiency of a
DMU 0 can also be measured using the DEA-scores calculated by CRS- and VRS models:
*VRS
o
*CRS
oo (3)
One of the biggest advantages of DEA is the possibility to integrate various multidimensional
inputs AND outputs into the efficiency analysis. This is of special importance in the health
care sectors where the output is multidimensional and some inputs and especially the output
can hardly be measured in monetary terms. Furthermore, there is no need to specify a certain
type of production function. Since very little is known about the functional form of health
care production, the endogenous – so to speak empirical – way to identify the best-practice
frontier is another major advantage of this non-parametric technique.
DEA can also be used to measure productivity changes over time. Figure 6 illustrates how the
dynamic productivity change can be measured in a disaggregated way. DMU D, for instance,
is identified in both points of time (t and t+1). The technical efficiency of the inefficient DMU
D at time t is 0J/0Dt and 0M/0D
t+1at time t+1, respectively (θD
CRS* < 1). In order to assess the
dynamic productivity change of DMU D, its technical efficiency relatively to the frontier in
time t and time t+1 will be measured. The geometric mean of these two rates of change shows
Output
A
B
C
D
E
FVRS
FCRS
0
B’’ B°
Input
14
the change of the total factor productivity of DMU D (∆TFPD) over the whole period. This is
the Malmquist-Index of this particular DMU (MID).
Figure 6: Disaggregated Malmquist-Index
The Malmquist-Index can be separated into two measures of efficiency change, an efficiency
change („catch up‟) component and a technology change („frontier shift‟) component:
2
1
t1tDL0
J0
M0
K0
D0
J0
D0
M0MI (4)
The first term on the right hand side („catch up‟) of equation (4) measures the change of the
distance of DMU D to the frontier in time t+1 (0M/0Dt+1
) relative to the distance to the
frontier in time t (0J/0Dt). If the score for this catch up component is higher than 1, the DMU
has enhanced its relative technical efficiency, it has cough up.17 The term on the right hand
side of equation (4) measures the shift of the frontier over time. Values of this component
bigger than 1 indicate dynamic productivity gains within the sample or, so to speak, the
underlying production technology. Using the disaggregated Malmquist-Index one cannot only
identify the productivity change of every single DMU that are due to individual efforts but
also efficiency changes that are due to technological progress or other factors that influence
the productivity of the whole sample. Again, this tool is very useful to assess the efficiency of
productive entities in health care because it incorporates a relative efficiency concept and can
handle multidimensional inputs and outputs.
17 If the score for the catch up component iss maller than 1, one actually had to call it „fall behind‟.
Input 1
Input 2
At
Bt
Ct = C
t+1
At+1
Bt+1
Dt
Dt+1
0
FCRS – time t +1
FCRS – time t
J
K
L
M
„catch up“ (∆E) „frontier shift“ (∆F)
15
Efficiency analysis in health care – some applications and results
Because of its specific advantages, during the last 20 years, Data Envelopment Analysis and
other non- or semi-parametric approaches have been used increasingly to measure the
efficiency of health care services. The vast majority of these studies focus on certain facilities
such as hospitals (e.g. Grosskopf and Valdmanis 1987, Borden 1988, Ozcan and Luke 1993,
Burgess and Wilson 1995, Grosskopf et al. 2001, Biorn et al. 2003 and Prior 2006), nursing
homes (e.g. Nyman and Bricker 1989, Kooreman, P. 1994, Rosko et al. 1995 and
Chattopadhyay and Ray 1996) or primary health care centers (e.g. Huang and McLaughlin
1989, Szczepura et al. 1993 and Athanasios et al. 2002).18
Interestingly, there are not many applications of non-parametric techniques to measure and
compare the efficiency of health care systems as a whole.19
Färe et al. (1997), analyzing a sample of 19 OECD countries, found a very widespread and
rapid productivity growth between 1974 and 1989 among the 10 countries with complete data
with Denmark and the US showing the highest cumulative productivity growth in this period
(> 30%). The main driver of this productivity growth was technical change.
Alfonso and St. Aubyn (2006) estimate semi-parametric models of health production using a
DEA-based two-stage approach for OECD countries for the years 2000-2003. Input variables
include medical technology indicators and health employment. Output is measured by
indicators such as life expectancy and infant mortality. The authors use a principal component
analysis (PCA) of the outputs life expectancy, infant survival rate and potential number of
years of life not lost. This reduces the dimensionality of multivariate output to one single
measure which has its advantages when the sample size is relatively small. However, by
running PCA one gets an artificial output measure that might not represent the output of every
health care system well enough. In the basic model, among 21 OECD countries, Canada,
Finland, Japan, Korea, Spain, Sweden and the US show the highest efficiency. The efficiency
of the Czech Republic, the Slovak Republic and especially Hungary falls way behind the
sample median. Inefficiency in the health sector has been found strongly related factors that
are, at least in the short to medium run, beyond the control of the health system: the GDP per
capita, the level of education, smoking habits, and obesity. In a next step, the authors take into
account differences in national income, obesity and tobacco consumption and correct the
efficiency score for these factors. Comparing the ranks and efficiency scores of the
uncorrected model with the scores and ranks resulting from the correction, significant changes
occur. Some countries poorly ranked previously are now closer to the production possibility
frontier – e.g. Denmark, the Czech Republic, Hungary, the Slovak Republic, and the UK. On
the other hand, countries like Canada, Japan, Sweden and the US receive remarkably lower
efficiency scores after the correction.
18 For a review of non-parametric studies in health care see Hollingsworth et al. (1999) and Hollingsworth
(2003). 19 Gupta et al. (1997) use an approach that is similar to DEA (free disposal hull – FDH) to analyze the
efficiency of government spending on health and education in Africa with life expectancy and infant
mortality as the main outputs.
16
Spinks and Hollingsworth (2005) go even further in integrating socioeconomic factors into
the models. They use measures for education (school expectancy years), employment
(unemployment rates), and income (GDP per capita) as inputs, additional to total health
expenditure. Life expectancy at birth is the only output. The authors calculated the technical
efficiency of OECD countries based on the data provided by the OECD and the WHO
respectively. In the WHO setting, they use a different output measure (disability adjusted life
expectancy – DALE). Turkey, Mexico, Korea, Greece, Spain and Japan reach full efficiency
in both models (OECD and WHO dataset). Italy and France lie on the frontier only in the
WHO setting. Iceland and Switzerland are identified as efficient only in the OECD setting.
The most remarkable efficiency deficits have been found for Denmark, the US, Belgium and
Germany.20
Spinks and Hollingsworth (2005) also calculate changes in efficiency between 1995 and 2000
(OECD dataset) and 1993 and 1997 (WHO database) using the disaggregated Malmquist-
Index. The mean value of the catch up component is 0.961 for the OECD dataset indicating
that overall, member countries have moved slightly away from the frontier, representing a
decrease in technical efficiency. Similarly, the mean technological change value (frontier shift)
of 0.995 would suggest that that the efficiency of the whole technology has declined slightly.
Overall, the mean efficiency of the whole sample have decreased between 1995 and 2000
(mean Malmquist-Index = 0.956). Interestingly, results using the WHO dataset move
conversely to results for the OECD dataset. Overall, the technical efficiency has improved
(mean catch up component = 1.041), whereas the efficient frontier has retracted (mean
frontier shift = 0.974). The total factor productivity seems to have increased slightly between
1993 and 1997. (MI = 1.014). Looking at the individual scores of the disaggregated
Malmquist-Index calculated by Spinks and Hollingsworth (2005) on the basis of the two
different datasets draw a rather dubious light on the results since for the majority of countries
the scores move to the opposite direction using the two different datasets. Since the two
periods do not differ considerably, the odd result maybe due to the different output measure
(OECD: life expectancy, WHO: DALE).
Both approaches discussed above (Alfonso and St. Aubyn 2006; Spinks and Hollingsworth
2005) incorporate broad socioeconomic or life-style measures more or less explicitly into the
efficiency analysis. As argued before, some measures of socioeconomic status, such as the
average income, the level of overall economic development, education and environmental
factors have clearly shown to be associated with health status (Macintyre 1993, Kaplan et al.
1996, Laporte 2002). In other words, different countries may face different individual
efficiency frontiers. That is why the idea to correct the efficiency scores for some important
factors that cannot be influenced by the health care system, at least not in the short run,
follows the concept introduced above (see again Figure 3). However, the dramatic changes of
the ranks and especially some individual efficiency scores due to the correction draw a rather
dubious light on the methodological approach used by Alfonso and St. Aubyn (2005).
Furthermore, integrating factors that are not under control of the productive entity to be
20 Notice that some of these findings are quite contrary to the results documented by Alfonso and St. Aubyn
(2006).
17
assessed directly into the efficiency analysis (Spinks and Hollingsworth 2005), is in conflict
with the very nature of efficiency analysis.
Towards a concept to measure the efficiency of health care systems – discussion
Efficiency in health care is relative. That is why the actual performance of a health system has
to be assessed relative to the performance of a group of peers that can be reasonably
compared to the system under evaluation. Although factors that lie outside the boundaries of
the health system might be even more important in determining the health status of the
population than the actions performed by the health system, it does not make sense to
incorporate factors that cannot be controlled by the decision makers within the health system
into the efficiency analysis, at least not explicitly as inputs. However, these factors surely
have to be taken into account when it comes to an assessment of the (relative) performance of
the health system. Therefore, we suggest a clear cut two-step procedure. First, the relative
efficiency of health care systems has to be measured by including all inputs that are used to
actually produce the output. Since the output of health systems is multidimensional, it might
be not enough to focus solely on life expectancy or other rather broad measures of the health
status of the population as the output measure. It could be necessary to integrate some of the
secondary outputs (e.g. some health actions that have been actually performed) into the
analysis in order to get a reasonable and fair evaluation of the efficiency of health systems.
This is not least due to the diminishing marginal returns to investment in health care that most
probably causes a lower marginal, though not necessarily average, productivity in countries
that already invest a lot into the health system.
Once the efficiency of the health systems has been calculated on the basis of factors that are
under control of the health system, the causes of differences in the relative efficiency can be
investigated, using regression analysis with the efficiency scores as the dependent variable
and certain socioeconomic and other factors as explanatory variables. The results can be used
to further elaborate and interpret the efficiency assessment. Using an appropriate research
design, one may even calculate specific elasticities of certain factors that affect the efficiency
of health care systems. These elasticities could be used to correct the efficiency scores derived
in the first step in order to take into account the different best practice frontiers the different
countries might face.
Because of its relative and non-parametric concept and the possibility to integrate multiple
inputs and outputs of different dimension into the analysis, the Data Envelopment Analysis
(DEA) is a very appropriate and powerful tool to assess the efficiency of health care systems.
Chapter on the design or reference to the second paper
18
19
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