12.2 Measuring health needs*
Oxford Textbook of Public Health
Measuring health needs*
Gavin Mooney, Stephen Jan, and Virginia Wiseman
The concept of need within the context of public health
The purpose of measuring need
Need in the clinical setting
Need at the level of the population
Need from a planning perspective
Measuring need—available instruments and their application
There is a beguiling simplicity about the proposition that health care services should be designed to meet the needs of the community. Faced with the obvious appetite for health care exhibited by virtually all communities exposed to it, it is traditional to distinguish between wants and needs: wants, by implication, being less rational, possibly even related to greed. Needs, by contrast, are seen as objective states, things that can be measured and agreed upon by rational people often on behalf of those who have them, as deserving attention.
The purpose of this chapter is first to explore the concept of need from several perspectives relevant to its interpretation within a public health framework. The purposes for which need might be measured—for action in the clinical and population settings and for planning—are then reviewed. Some currently available measures of need are then examined and some conclusions are drawn.
The concept of need within the context of public health
It is clear that need can be viewed in many different ways. A community experiencing high levels of infant mortality due to tetanus might be seen by a preventivist as one in need of the development of an effective maternal education programme focusing on hygiene at the time of the cutting of the umbilical cord and maternal immunization. Conversely, an intensive care physician may see the same phenomena and compute them in terms of needs for neonatal intensive care beds to effect rescue of the young victims. The individuals involved—the parents of the children affected—may have a third interpretation of what they need, which may have little to do with child survival.
These constructs of need—which is what they are, melding essentially the same ‘facts’ into different shapes—each have their legitimacy. Unless health is to be seen as something occupying a quiet biological space, independent of culture and society, then these different constructs need to be accepted. Each derives from the fact that any relevant concept of need is value laden. Definitions of need vary depending on whose perception, interpretation, and values are in play. There is also the question of whose values ought to come into play and in which circumstances. It is most unlikely that some universally valid construct of need can be adopted that will be apposite in all circumstances.
This becomes still more obvious when it is recognized that need cannot exist without addressing the question of ‘need for what?’ Need is thus best seen as being both value laden and requiring specification of the instrumentation for needs to be addressed or met. Health needs can be addressed and met through treatment services, rehabilitation services, caring services, prevention at an individual level, community health promotion activities, environmental protection, and in many other ways. Health needs are thus most commonly set in the context of a need for care, but in the wider context of public health, need may be more inclusive.
There is immediately a problem, seemingly at both an analytical level and a policy level, with respect to instrumentality (i.e. the instrument by which the need will be met). It is much easier—and relevant literature supports this view—to measure need when the instrument is health care than when the need is satisfied by an instrument using mechanisms not normally encountered within health services. It is with respect to non-health service, public health needs, that analysts and policy-makers seem to hit major problems of conceptualization (although given what has been said above this ought not to be the case) in particular with regard to assessment and quantification.
A fundamental point needs to be made at this juncture. Need is most frequently seen as being formed or perceived in the eyes of another, a third party. Thus, Liss (1990) wrote ‘A need for health care exists when an assessor believes that health care ought to be provided’.
This statement neatly combines two important aspects of need. Firstly, it incorporates the notion of the instrumentality of need. The need is for health care but it is not health care that is the ‘final goal or objective’. It is not, from the patient’s point of view, health care per se that is wanted. The patient wants health and uses the ‘instrument’ of health care to try to obtain it. Secondly, Liss’s statement embraced the notion of a third party doing the assessing. With this conceptualization of need it is not the patient who is doing the assessing but someone else, an agent (often a medical doctor), on behalf of the patient. (While it would be possible to deduce from the quote from Liss (1990) that need might be self-assessed, it is clear elsewhere in his and in much other literature in this area that is not what he intends.)
Such third-party assessment requires, for the assessment to have legitimacy, that wider concerns are at play. If a doctor, for example, assesses a patient’s needs, this is only of interest if that assessment leads to rights for the patient or clarification or quantification of rights which then provide the patient with access to services which might be of assistance in addressing the problems indentified by the doctor. It is not the assessment by the doctor that provides the needs with their rights base, with their element of ‘social legitimacy’. That can only come from the concept of a social contract. When it is claimed that individuals have a right to certain basic necessities, that is the language of a social contract. As Loewy (1990) stated ‘Social contract consists of those things which“go without saying” and which we consider to be the legitimate expectations we have of others and of our community’.
Tension arises with respect to what sort of community it is in which we are trying to assess needs. As Loewy (1990) reminded us, according to the Aristotelian dictum, ‘justice consists of giving everyone their due’. He continues, however:
What is and what is not someone’s due…is another matter. Minimalist communities which…accept freedom as an absolute condition of the moral life will see what is due quite differently than will more generously based communities. What is due in minimalist communities is doing each other no harm; what is due in broader based communities is a far more difficult matter and one which will ultimately be determined by an ongoing dialectic between communal values and individual interests.
It immediately follows that the separation of wants and needs, which for some seems so simple, in practice is far from simple. There is an astonishing lack of research into individuals or communities as to what they actually want from their health care services and so the pejorative view of wants as little more than expressions of greed by the ignorant is particularly unfortunate. Paternalistic professionalism has blocked progress in understanding how the community views health and health care and where they place them in the context of other things that they also want for their lives.
Distinctions between needs and wants are made still more difficult by the fact that different disciplines also use different definitions. A potentially useful set of constructs is provided by the discipline of economics. Wants are the preferences of individuals on behalf of themselves but do not have to be expressed through taking action to have the wants ‘fulfilled’. ‘Demands’ are based on wants, that is on an individual’s own preferences, by some action on the part of the individual in seeking to have the wants addressed. Thus, a want for better health can be expressed as a demand for health care if the individual visits a general practitioner. A need for health care would arise if the general practitioner were to agree that some relevant action could be taken by the health care services on behalf of the patient. It is clear that need could exist without want or demand, demand could exist without need but not without want, and want could exist without demand or need.
This distinction between need on the one side and wants and demands on the other emphasizes still further the value-laden nature of these phenomena. Such emphasis is merited. While wants and demands are normally readily recognized as being value laden, this is less commonly the case with the conceptualization of need.
Need is also likely to be dynamic over time. The need for care today, for example, is very different from the need for care 20 years ago. Partly, it is that the incidence and prevalence of diseases have changed. Also, expectations and values of both the population and the health professional have changed. Technological change and changing availability of services have also altered the extent and pattern of needs. Similarly, needs are likely to vary in moving from one culture or one society to another.
Policy and research in public health have not often adopted a multidisciplinary approach to the understanding of either wants or needs for health care. A great deal of ignorance thus lies undisturbed and the strengths and limits of the various public health sciences and discourses are thrown into relief when each comes to examine the nature of need. Epidemiology, with its reductionist roots, can provide a count of cases, deaths, and denominators, and can also provide insights into some of the causal pathways that manifest as these health states that we declare as needs. The social sciences can provide an interpretation of needs in terms of how society views departures from health—ranging from their perception as religious events through to secular phenomena that require government intervention that reinforces social values such as equity and efficiency. As indicated above, health economists can contribute to the understanding of health needs by setting them within the context of what demands individuals and society place upon the resources available to them, in terms of their individual and corporate happiness and satisfaction. For example, where do health needs fit in the total spectrum of needs, alongside the basic ones in the lower orders of the Maslow hierarchy (food, shelter, etc.) and in relation to the more sophisticated ones for education, justice, and freedom of speech?
Any simple interpretation of need must therefore be suspect. The reductionist quality of measures of need should be understood if we are to avoid making useless extrapolations from them. Nevertheless, reductionist measures of need share with much reductionist science a remarkable capacity to get the job done, things improved, wars won, and health status elevated. The major issue confronting those involved in public health, therefore, is not so much to search endlessly for an all-embracing definition of need, but to be willing to live with pared-down versions of need that may be useful within a particular context, whilst recognizing their limitations. The debate about measuring need therefore shares much with the debate about measuring the quality of life.
What is not to be applauded, however, are those interpretations of need which are driven by data availability rather than the purpose for which the need measure is required. There are too many examples in the literature of needs estimation based on inappropriate grasping at available numbers without due consideration as to whether in ordinal or cardinal terms the interpretation of the numbers does reflect the construct of need which is claimed implicitly or explicitly.
The purpose of measuring need
If we accept that the generic notion of need is complex and elusive we can proceed to identify different settings in which different measures of need, each with their limitations, may prove useful.
Need in the clinical setting
Within clinical practice, the measurement of need is an integral part of the daily routine. It is a necessary and accepted part of such practice.
The relevance of need and its usefulness in clinical decision-making are obvious and seemingly unchallenged and unchallengeable. Yet a challenge does arise from the extent to which there are substantial variations in such clinical practice for similar or even identical health conditions. At this level, seemingly similar problems—identified perhaps with respect to reduced health status—are interpreted quite differently by different clinicians in terms of what is needed to deal with them. Manifestations of such apparent variations in interpretation can be a function not only of diversity in respect of need but also of availability of resources to treat particular problems.
However, variations in the rates of performance of various surgical procedures exist to a very great extent even after allowing for or controlling for variations in the supply of resources and the qualities of the populations being served. There is little doubt that this is a function of differences in perception and/or interpretation of needs at a clinical level across different clinicians.
In the face of a value-laden concept of need, the ‘medical model’—if A, then B—can appear somewhat mechanistic. Neither A (the diagnosis) nor B (the choice of therapy) are devoid of value judgements on the part of the clinician. Yet recently it was possible to read into the concept of need in clinical medicine something that appeared concrete, objective, and largely value free.
At the very heart of clinical medicine lies an increasing recognition of the extent to which medicine is about values, including the assessment and interpretation of needs.
At a clinical level there will be variations in interpretations of need across similar conditions but in different cultures. The fact that this occurs within cultures, and further, can very clearly be influenced by the nature and structure of incentive systems (and not just financial incentives), emphasizes still more the subjective nature of need. It is not possible to interpret the results of various studies on changes in remuneration systems in any other way. Need at a clinical level is a function, among other things, of how doctors are paid.
To point this out is not to criticize or to express regret about such a phenomenon. More importantly it is to recognize that there is potentially a useful tool for influencing clinical practice, in terms of not only the effectiveness of that practice but also its efficiency and its contribution to concerns for equity. Given the central place of need in clinical decision-making, the fact that need can be perceived differently within different remuneration systems (Krasnik et al. 1990) has to be an important consideration for policy-makers. Yet the potential for using the remuneration system for policy purposes has been underexploited to date.
Need at the level of the population
Although need may be considered in absolute terms, it is principally in relative terms that it finds its place in contemporary health service development and appraisal. Thus ‘standardized mortality ratios’, that is mortality rates standardized to some common population, are compared from one region or country to another and implications are drawn about need. A community that has a 10 per cent higher mortality rate from ischaemic heart disease than the national average is seen, in particular by the popular press, as being ‘in need’—of more coronary care beds, or more preventive programmes, or more ambulances fitted with defibrillators, etc.
Need is defined in these settings as some correlate of mortality, in no small part because mortality statistics despite all their weaknesses are, like democracy, pretty good compared with anything else.
Where there is a problem at this level is with respect to answering the instrumentalist question: ‘need for what?’ Other things being equal, a higher level of mortality implies a higher level of need in some general rather unspecific sense—but greater need for what? It might be for health services but perhaps also for many other goods, services, or activities. We believe that in the continuing tension between, on the one hand, treatment services for meeting health needs and, on the other hand, public health services, one of the reasons why the latter may ‘lose out’ in resource allocation is the failure to specify needs adequately in terms of instrumentation. Instruments or interventions in treatment services tend to be of a much more specific and identifiable nature than is the case with public health measures. The former are also drawn from a defined set of health care services whereas public health interventions can be present in very many areas of the economy—transport, housing, the environment, food policy, etc.
Doctors working in the acute hospital sector always have seductively simple and clear instruments at hand. In the battle for meeting needs at that level as opposed to the public health level they have the imperative of current sickness to provide still more weight to their claims over a still greater share of society’s scarce resources. The latter is difficult to push aside and there are arguments that in the context of rescue, there is no reason to push them aside. It is important, however, to decide the extent of influence since it cannot be the case that treating current sickness can be seen as an absolute or at least ought not to be.
Need from a planning perspective
There are two places where need impacts upon planning. The first is in relation to what economists refer to as ‘allocative efficiency’. This involves first an acceptance that resources are scarce, and second that the over-riding goal is to maximize benefits with the available resources. In terms of needs this presumably translates as maximizing the needs met or the value of the needs met with the resources available.
The second place where need and planning converge is in the pursuit of equity. In relation to equity, issues of distribution are often set in terms of ‘equal use for equal need’ or ‘equal access for equal need’.
For allocative efficiency the health service planner approaches need as but one ingredient in a complex equation which he or she is expected to solve. In this context, the planner may identify ‘need’ as being those margins of existing programmes for which additional resources might achieve more than similar sized investments in other programmes. A further implication of this is that there may be situations for which resources might be withdrawn and devoted elsewhere with greater well being than is currently derived from the system.
The following statement might be made: the returns to health of monies spent here, on this programme, in this location, on this group of patients, on this effort on prevention, are not high enough—the money would be better spent over there on that other programme, on that other group of patients over there. If it is possible to take $100 000 from the treatment of cancer patients and do still more good in treating the elderly for, perhaps, chronic arthritis, then it should be done. If the reverse is true then the direction of the resource shift should be reversed.
It is not enough to be able to say that resources which are scarce are being well spent; the issue is rather, could they be better spent? Are there more needs or more highly valued needs that resources could be used to address?
The idea of shifting resources to where they can meet the greatest need (or more correctly where they will do most good)—what economists call marginal analysis—is not difficult to grasp. If more good can be done than is being done, if more needs can be met with the same resources, then the argument is that that is what should be done.
It is here that the need for measurement of need becomes paramount as judgements have to be made about where resources will meet the greatest need. If, with the same amount of resources, pain, suffering, and death can be reduced still more, then let us do so. That is the simple notion of economic efficiency.
The concept of need incorporated into this planning framework is that of capacity to benefit (Culyer 1991). Here it is argued that if individuals have a capacity to benefit from a particular service then they have a ‘need’ for that service. This is a somewhat different type of need as compared with that which is used frequently at the population level and is interpreted in terms simply of the extent of illness and death in a population (as described above). Even if a health problem exists, if there is no capacity to benefit, under this definition there is no need.
This planning framework stands to benefit if we can obtain a picture of how resources are currently being spent and linked in an appropriate way to what the objectives and priorities are. This picture is what is known as a set of ‘programme budgets’.
Most commonly in health care, expenditure data are available categorized by inputs, for example, expenditure on doctors, nurses, pharmaceuticals, and linen. In programme budgeting the interest is in categorization of sets of needs that we seek to alleviate or meet—the needs of the elderly, children, cancer patients, etc. The link is thus between expenditure and health objectives for relevant social or disease groupings.
Therefore, prior to proceeding with the marginal analysis or shifting resources, it is relevant to find out what is being spent on these groupings or ‘programmes’. The two keys to designating programmes are first that the programmes together are comprehensive in that, first, all the health services—hospital, general practitioner, and community—are included, and second, the programmes are output or outcome orientated and not input orientated as is the case with most forms of budgeting.
This approach—programme budgeting plus marginal analysis—is what economists recommend for use in pursuing the meeting of needs at a planning level (Cohen 1994; Health Policy 1995). With respect to the marginal analysis part of the approach, trying to form a judgement about whether $1 million is better spent on maternity care rather than on care of the elderly is difficult. There are major measurement problems here and greater effort needs to be invested in developing appropriate measures to enable these comparisons to be made.
Quality-adjusted life year (QALY) league tables may be seen as a form of marginal analysis. Such tables allow comparisons to be made between conditions according to the impact they have on the quantity and quality of life of sufferers. As discussed in more detail below, the QALY, which discounts chronological survival according to the quality of life, has also been used as an output currency to compare what is attainable for investment in various health care procedures. Thus, for $10 000 spent on treatment for one condition one may purchase 300 QALYs, compared with 700 QALYs for the same price if one is treating a different condition. Yet QALY league tables have limited applicability in resource allocation contexts for several reasons (Gerard and Mooney 1993). For example, at the most practical level cost–utility studies, which form the basis of the QALY league tables, are relatively sparse.
The moves in, for example, the United States (through the Patient Outcome Research Team programme etc.), the United Kingdom (in particular Wales), New Zealand, and New South Wales in Australia, to plan health services with the focus on health outcomes or health gain, place emphasis on efficiency and equity in the context of needs. Such an emphasis demands that objectives be more precisely and explicitly stated and needs identified more carefully and quantified. It is to the quantification of needs that we will turn shortly.
Other possibilities exist at the planning level for meeting needs. For example, in the United Kingdom there is enthusiasm at present for ‘needs assessment’ by which the needs of the population are expressed in terms of the burden of illness attributable to several major diseases. Resources are then allocated in proportion to the size of the needs. However, this method appears to fail to consider the effectiveness of interventions to meet those needs. Nor does it directly confront the costs of interventions and so it is not clear how this method could achieve the most wise use of resources as discussed above. This thinking also underlies the World Health Organization (WHO) and World Bank initiatives on burden of disease. These issues are discussed more fully by Shiell et al. (1987), Mooney and Creese (1993), Murray and Lopez (1997), and Wiseman and Mooney (1998).
Attempts to reallocate limited Medicaid dollars to a wider pool of recipients in Oregon have attracted great attention, in no small part because need, effective therapy, and cost have been subject to public scrutiny in determining a pattern of resource expenditure for health care (Dixon and Welch 1991; Kitzhaber 1993). In 1991, after extensive consultation, a proposal was put forward that Medicaid coverage for the poor in Oregon should cease to cover everything possible for the poorest 200 000 recipients of aid and instead provide for 709 disease categories and paired treatments for an additional 100 000 recipients. The plan was approved by President Clinton on 19 March 1993.
Contrary to what many might have expected, the Oregon Health Plan still survives. Its resilience can be explained partly by its rather pragmatic adherence to the rationing criterion of restricting coverage to services above a cut-off point (Jacobs et al. 1999).
Teng (1996) argues that the compromises which led to the development of the list of services to be covered meant that the original objective of cost-effectiveness was largely undermined. Regardless of how the list was devised, however, it is doubtful whether cost-effectiveness is compatible, in general, with an approach to funding that partitions services above and below a fixed line. Its main limitation is that it takes no account of differences across individuals in terms of their capacity to benefit from the same treatment.
Despite this, the Oregon Health Plan has been successful in one of its major objectives: of increasing medical coverage across the state (Oregon Health Plan 1997; Jacobs et al. 1999; Leichter 1999). Conversely, it has been less successful in reducing overall health care expenditure and has relied to a large extent on funding from increases in tobacco taxes (Jacobs et al. 1999).
The second consideration that planners will be interested in concerns equity. One of the most problematical aspects of this is that there is so much confusion in health care policy circles as to what this word means. The chief contenders are ‘equal health’, ‘equal use for equal need’, and ‘equal access for equal need’. Clearly the last two of these incorporate some view of need within them. Here our concern is restricted to the relationship between equity and need and, within that, the issue of resource allocation formulas.
The international industry of needs-based (or weighted capitation) resource allocation formulas began with the Resource Allocation Working Party (RAWP) in England whose report was published in 1976 (DHSS 1976). The approach has been used in several other places since (e.g. New South Wales in Australia and New Zealand) and has recently been reviewed in the United Kingdom (NSW Health Department 1996; DoH 1997, 1999).
What the original RAWP sought was a formula for allocating resources fairly to the 14 geographical regions of England based on the principle of equal access for equal need (although in practice it did not go beyond equal expenditure for equal need). The RAWP formula (and the various versions it has spawned) emphasized horizontal equity, i.e. equity that ensures that individuals with similar characteristics are treated equally. Vertical equity—the unequal treatment of unequals—is not included directly in the formulation except in so far as different needs are weighted by the cost of dealing with each.
A recent paper (Mooney 1998) argues that there may be a case for developing the notion of ‘communitarian claims’ to replace needs or at least to complement them. It is normally the case that need is conceptualized in terms of purely health and that in meeting need all nominally equal health gains (such as QALYs) be weighted equally. Communitarian claims, it is suggested, allow for other considerations (e.g. information or respect for patient dignity) to enter and for health gains to some recipients (e.g. those in particularly poor health) to be weighted more highly than others. A further claimed advantage is that it is the community who determine first what constitutes claim, and second the differential strengths of different claims. These would determine what health care resources were to be made available to different groups in society. These claims are communitarian not only in the sense that the responsibility to arbitrate over them lies with the community but also that it is beneficial to the community that they do so. For example, in Australia the overall community may feel better as a result of knowing that it has contributed to the betterment of the health of its indigenous peoples.
Measuring need—available instruments and their application
In several countries measures of need have been constructed to guide the allocation of health care resources. The methods vary from allocating resources to geographical areas on the basis of prevailing patterns of mortality and social class, through to case-mix payment to hospitals on the basis of the need (in terms of diagnosis and severity) of patients admitted to their care.
The approach adopted in the RAWP (see above) aimed at measuring relative (and not absolute) need for health care in different regions. Such health care was divided into seven categories: non-psychiatric inpatient services, all day-patient and outpatient services, mental illness inpatient services, mental handicap inpatient services, community services, ambulance services, and administration of family practitioner (general practitioner) services, but not these services per se.
The relative need for each of these services in each region was calculated on the basis of a formula which weighted the population according to a number of factors. For example, the factors relevant to non-psychiatric inpatient services were size of population, age/sex composition, morbidity (although in practice this was actually the standardized mortality rate), cost, patient cross-boundary flows, medical education, and capital investment.
Relative need was calculated for each of the services listed and then weighted according to the national proportion of the total cost being spent on that service. These were then summed to give a regional overall weight. Thus, if a region with a population of, say, 5 million was above average in terms of need, for example to the extent of 10 per cent, then it would receive funding which assumed a weighted population of 5.5 million.
In 1993 in New Zealand, in the wake of the establishment of regional health authorities, the emphasis shifted from funding for individual services to funding for a region’s needs. More attention was focused on providing resources for an equitable level of services across the country (New Zealand Ministry of Health 1998). This new way of funding health and disability services has continued even though the four regional health authorities have been merged to form the Health Funding Authority.
The total amount of funding for New Zealand’s health and disability services is distributed between the four health funding authority regions using three population-based funding formulas—one for personal health, one for public health, and one for disability support services (New Zealand Ministry of Health 1998). The formulas are used to determine each region’s population, broken down into age, sex, and ethnic groups, and to weight this population according to the cost of providing services to each of the age/sex/ethnic groups.
What these formulas assume is that the total relative need in a region and across regions is a meaningful entity and that is open to challenge. It further assumes that the relative total need can be measured sufficiently accurately by just a few factors. Thirdly, it assumes that using standardized mortality rates as a measure of relative morbidity is a valid measure (again a doubtful assumption as indicated previously).
We would not want to appear overcritical of this process. What we would emphasize is the desirability in many instances of trying to fund health services on an equitable basis and that using some concept of need is the way to follow. It remains the case, however, that the assumptions typically used in needs-based formulas and the problems of measurement are such that we are less than convinced that this is the best way to proceed. In particular we would submit that weighting different needs according simply to cost rather than social value remains problematical.
Measuring needs, as indicated above, is likely to be problematical for the various reasons already stated. Whatever process is adopted, it involves establishing a measure of some shortfall in health status which from some ideal, from some norm, from some achievable health status, or some measure of ‘capacity to benefit’.
There are many ways of trying to measure needs which are severely deficient and reflect more the availability of data than any real attempt to grapple seriously with the conceptualization of needs as spelt out so far in this chapter. Various activity measures—numbers of hospital admissions, visits to general practitioners, vaccinations carried out, etc.—are sometimes used to measure need. Yet it is readily apparent that such indicators reflect not only need (although visits to general practitioners may perhaps be designated a measure of consumer demand, in particular first visits) but also supply side considerations such as availability and appropriateness of services.
Certainly there are a number of vehicles that can be adopted to allow measurement of need to take place. Most common here would be epidemiological and social surveys. The question then is how to measure needs within any such survey. Two possible measures here are the QALY and the Short Form 36 (SF-36).
The QALY, and its more recent ‘stable mate’ the healthy year equivalent, have been developed largely by economists (Williams 1985; Torrance 1986; Mehrez and Gafni 1989) to allow health status to be measured in various circumstances. Both are based on the concept of health-related utility which recognizes that health, as an output of health services and of other activities that promote health, is a function of both quantity of health and quality of health—or mortality and morbidity.
The QALY allows individuals, groups, or societies to ‘trade-off’ quantity of life against quality of life arguing, for example, that according to people’s preferences 10 years living with a chronic condition which results in the individual being confined to his or her own home is equivalent to 8 years of full health. The implication is that the ‘quality adjustment’ for the chronic condition is 0.8. Furthermore, it is implied that intervening to cure the chronic condition would result in an improvement in quality of life of 0.2 per annum which over 10 years means 2 QALYs.
While there are various criticisms that can be made of QALYs (Loomes and McKenzie 1989), they do have considerable merit over the more conventional measures of health status and of need such as mortality rates or standardized mortality rates in that they do endeavour to combine both quantity of life and quality of health. The development of QALYs has helped to gain greater acceptance for the point that health status, and in turn need, have large subjective elements and are value laden. In practice, to date QALYs have been used to measure need, essentially marginal-met need, in the context of priority setting through QALY league tables, as discussed above.
The disability-adjusted life year (DALY) is a variant of the QALY. DALYs were first introduced by the World Bank in 1993 (World Bank 1993) as a means of calculating the burden of different diseases. The approach involves the measurement of health status (strictly lost health status) into a universal index of mortality and morbidity.
Specifically, the DALYs for a given condition or disease are the sum of years of life lost due to premature mortality and the number of years of life lived with disability, adjusted for the severity of the disability (Murray and Lopez 1997). In terms of the disability severity weights, these were originally based on the opinions of experts in international health and fell into six classes of severity ranging from 0 (for perfect health) to 1 (for death) but, more recently, social values have been incorporated in DALYs (Murray and Lopez 1997).
DALYs and their use as an aggregate measure of health status in the monitoring of population health, in the establishment of priorities between interventions, and as a guide to research priorities have been criticized by a number of authors. Prime among the criticisms made are that DALYs inadequately reflect social preferences for health, that all they reflect is health and not other possible outcomes or valued processes from the health care system, that the assumed or posited goals of health care systems are not validated, that such goals are constant across all societies, and that using DALYs, as is advocated, to measure the burden of disease to assist with priority setting is at best a misuse of analytical resources and at worst potentially misleading (Shiell et al. 1987; Mooney and Creese 1993; Mooney et al. 1997; Sayers and Fliedner 1997; Wiseman and Mooney 1998; Williams 1999).
The SF-36 was developed by the RAND Corporation in the United States for use in the Health Insurance Study Experiment/Medical Outcomes Study (Ware et al. 1993). It is a concise 36-item health-status questionnaire and has become one of the most widely used measures of subjective health status (Ware et al. 1993; Jenkinson et al. 1996; Jenkinson and Layte 1997).
The SF-36 contains 36 items which measure eight dimensions: physical functioning (ten items), role limitations due to physical problems (four items), role limitations due to emotional problems (three items), mental health (five items), energy/vitality (four items), social functioning (two items), pain (two items), and general health perception (five items). There is also a single item about perceptions of health changes over the past 12 months.
The validity and reliability of the SF-36 in patient populations has been confirmed in the United States (McHorney et al. 1992, 1993). For example, patients with chronic heart failure reporting oedema, orthopnoea, or dyspnoea on exertion were classified as having a serious medical condition. The SF-36 could detect differences in health status among these patient groups across all eight scales. Garratt et al. (1993) claim on the basis of their own empirical work in the United Kingdom that the SF-36 seems ‘acceptable to patients, internally consistent, and a valid measure of the health status of a wide range of patients’.
However, not all studies have been favourable to the SF-36. For instance, it has been criticized for failing to detect low levels of morbidity in some patient groups (Bowling 1997). Kurtin et al. (1992) reported ‘floor’ effects in the role of functioning scales in severely ill patients, where 25 to 50 per cent of patients obtained the lowest score possible, the implication being that deterioration in condition will not be detected by the scale. Other studies have revealed that it has little discriminatory power among women receiving different treatments for stage II breast cancer (Levine et al. 1988; Guyatt et al. 1989). Detailed reviews of the instrument are given by Anderson et al. (1993) and Bowling (1997).
More recently, an abbreviated version of the SF-36, the SF-12, has been developed (Ware et al. 1995, 1996a,b). The SF-12 health survey generates the physical and mental component summary scores of the SF-36 ‘with considerable accuracy, while imposing less burden on the respondents’ (Jenkinson and Layte 1997). However, there do appear to be trade-offs in terms of reliability. For example, Jenkinson and Layte (1997) warn that ‘the questionnaire contains a number of areas of health tapped with only a single item…consequently the SF-36 will provide a more reliable profile of scores across the eight domains than could be gained using the SF-12’.
Moreover, the simple scoring algorithms used in most of the non-preference-based measures of health such as the SF-36 assume first that there are equal intervals between the response choices, and second that the items are of equal importance (Brazier et al. 1999). As Brazier et al. point out, the SF-36 physical functioning dimension assumes that being limited in walking has the same importance as being limited in climbing flights of stairs. There is no reason for this to be the case. The SF-36 has the advantage of taking only 5 to 10 minutes to apply; thus it is easier to use than QALY measures.
Which measure is to be preferred in measuring need is not only a function of why need is being assessed but also the context or environment in which it is being assessed. Many normative factors influence health perceptions including the health of others in the individual’s community or group, the nature and severity of the illness, demographic characteristics, and social class (Festinger 1954; Berkowitz 1975; Twaddle and Hessler 1977; Wills 1981; Sen 1987; Crawford 1994). While many measurement efforts are mathematically sophisticated and some are reliable in the sense that they can reproduce the same results from one application to another, they tend to be of questionable validity in so far as they fail to recognize the importance of these normative factors. Currently, most health status indices do not take account of the variation in criteria that individuals or groups use to make health status judgements about their own health status.
The consistent underperception of ill health observed in many disadvantaged and marginalized groups has ‘obvious implications for the design and implementation of public health programs particularly if these programs aim to bring treatment to those most in need of such help’ (Wiseman 1999). Secondly, resource allocation decision-making which relies on subjective measures of health may provide a misleading picture of the resource requirements of some groups in society. This will have implications for estimating health care priorities and the funding and planning of health services. There is a need to learn more about the criteria of health which are relevant in judging the well being of these groups and to investigate alternative elicitation procedures which would allow for a more accurate reflection of the preferences of such groups.
The concept of need is elusive but useful. In confronting the notion of need, we acknowledge the value-laden quality of the community’s expectation of health services, whether these be for the relief and treatment of illness or the preservation and maintenance of good health. Need derives its meaning from the instrumental pathways we can follow in meeting it and inevitably involves third parties in its definition.
Need is a critical concept in the pursuit of efficient health care and equally critical to the development of services which are equitable.
Once need is admitted into the health care decision-making environment, other things follow. In determining how to meet need in a setting of limited resources, the allocation of those resources must take account of the likely health gain and the cost of that achievement. Moving resources at the margins of our principal programmes of care and health development, according to estimates or measurement of the cost and outcome, offers ways in which we can move in the direction of the wisest use of those resources in meeting community need.
*We are grateful to Steve Leeder for allowing us to use materials included in the previous version of this chapter which he co-authored with GM.
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