NICE process and methods

7 Assessing cost effectiveness

Health economics is about improving the health of the population through the efficient use of resources, so it necessarily applies at all levels, including individual clinical decisions. Clinicians already take resources and value for money into account when making clinical decisions; the incorporation of good-quality health-economic evidence into clinical guidelines can help to make this more consistent.

The Guideline Development Group (GDG) is required to make decisions based on the best available evidence of both clinical and cost effectiveness. This chapter describes the role of the health economist in the development of NICE clinical guidelines, and suggests possible approaches to considering economic evidence as part of the guideline development process. It also sets out the principles for conducting new economic modelling studies if there is insufficient evidence in the literature to assess the cost effectiveness of key interventions or services.

Guideline recommendations should be based on the estimated costs of the interventions or services in relation to their expected health benefits (that is, their 'cost effectiveness'), rather than on the total cost or resource impact of implementing them. Thus, if the evidence suggests that an intervention or service provides significant health benefits at an acceptable cost per patient treated, it should be recommended even if it would be expensive to implement across the whole population.

When implementing a guideline's recommendations, commissioners and trusts also need to know the resource and cost implications for their organisations. NICE undertakes a separate, but parallel, cost-impact analysis. This analysis is usually developed by the NICE costing analyst during the consultation period of the clinical guideline. Costing tools are published at the same time as the guideline, to allow organisations to estimate implementation costs (see section 13.1.3).

7.1 The role of the health economist in clinical guideline development

The health economist is a core member of the GDG alongside the rest of the National Collaborating Centre (NCC) or NICE Internal Clinical Guidelines Programme[11] team, and should be involved from the beginning of scoping (see chapter 2). The health economist should attend all GDG meetings.

Although the health economist has skills in economic analysis, the expertise of all of the GDG members will be necessary to ensure that economic evidence is underpinned by the most plausible assumptions and the best available clinical evidence. Similarly, the health economist may be able to provide input into the interpretation of clinical data and develop models to help assess overall health outcome.

The key role of the health economist in clinical guideline development is to:

  • advise on economic issues

  • review economic evaluations

  • prioritise questions for further economic analysis

  • collaborate with the systematic reviewer to develop evidence syntheses for input into economic models

  • conduct economic evaluations

  • liaise with the costing analyst at NICE to ensure consistency between the cost-effectiveness and cost-impact assessments.

The relative amounts of time spent by the health economist on each of these tasks will vary between guidelines. There are likely to be large differences between clinical guideline topics in the amount, relevance and quality of the economic literature. In some topic areas there may be high-quality data that can be used in economic models, whereas in other areas there will be little information.

Defining the economic priorities for each clinical guideline should start during scoping, and should proceed alongside development of the review questions. The NCC prepares an economic plan, which contains a preliminary overview of the relevant economic literature. The plan also identifies the initial priorities for further economic analysis and the proposed methods for addressing these questions (see section 7.1.3). It is prepared by the health economist in consultation with the rest of the NCC team and the GDG, and is discussed and signed off by NICE, usually within 3 months of the first GDG meeting. For short clinical guidelines the economic plan should be submitted to NICE 1 week after the first GDG meeting. The economic plan is likely to be modified during guideline development. For example, as the clinical evidence is reviewed it may become apparent that further evaluation is not necessary for some aspects that were initially prioritised for economic analysis. Any key changes in the economic plan should be agreed between the NCC and NICE. A document listing the final areas prioritised for economic modelling and corresponding PICO (population, intervention, comparator and outcome) questions should be sent to NICE 5–7 weeks before consultation on the guideline so that it can be published on the NICE website. The rationale for the final choice of priorities for economic modelling should be explained in the full guideline.

The health economist should ensure that the economic model(s) developed for the guideline are sent to NICE and are available to stakeholders during consultation on the guideline. These models should be fully executable and clearly presented.

7.1.1 Advising on economic issues

The health economist should encourage the GDG to consider the economic consequences of the guideline recommendations as well as the clinical implications. A formal presentation outlining the basic principles of health economics is given at the first GDG meeting, and further presentations may be useful later in the guideline development process. It is particularly important that the GDG members understand that economic analysis is not simply a matter of estimating the consequences of a guideline recommendation in terms of use of resources, but is concerned with the evaluation of both costs and health benefits. GDG members also need to understand that economic evaluation should compare the costs and consequences of alternative courses of action. 'Cost of illness' or 'burden of disease' studies are not useful for decision-making when developing clinical guidelines.

Cost effectiveness is assessed in order to maximise health gain from available resources. If resources are used for interventions that are not cost effective, then less health gain is achievable across the whole population (that is, there is a greater 'opportunity cost'). Within the context of the principles outlined in the document Social value judgements: principles for the development of NICE guidance (see also section 1.1.1), the GDG should be encouraged to consider recommendations for interventions that:

  • are less effective than current practice but free up a substantial amount of resources that can be re-invested in the NHS or

  • increase clinical effectiveness at an acceptable level of increased cost (see section 7.3).

The GDG members may find it useful if the health economist discusses with them other economic concepts, such as incremental analysis, the NHS and personal social services (PSS[12]) perspective, and measurement of health-related quality of life (HRQoL) and quality-adjusted life years (QALYs). The British Medical Journal has published a series of 'economics notes' describing other concepts that the health economist may wish to explore with the GDG (Raftery 1999–2001).

7.1.2 Reviewing economic evaluations

Identifying and examining published economic information that is relevant to the review questions is an important component of clinical guideline development. Processes for searching for, selecting, appraising and summarising economic evaluations are discussed in sections 5.3, 6.1.3, 6.2.4 and 6.2.5.

The general approach to reviewing economic evaluations should be systematic, but focused and pragmatic. If a high-quality economic analysis that addresses a key clinical issue and is relevant to current NHS practice has already been published, then further modelling by the health economist will probably not be necessary. This frees up time for modelling on other questions. However, many published economic evaluations will not be relevant; for example, costs in non-UK studies may differ from those in the NHS. Time should not be wasted on critically appraising studies that are not likely to provide useful information for guideline decision-making. Search strategies and inclusion and exclusion criteria for economic evaluations should be designed to filter out such papers (see section 5.3), and these strategies should be explained in the full guideline. The approach used should be explicitly stated in the full guideline and applied consistently.

7.1.3 Prioritising questions for further economic analysis

Only rarely will the health economic literature be comprehensive enough and conclusive enough that no further analysis is required. Additional economic analyses will usually be needed, in which case new analyses should be developed selectively, unless an existing analysis can easily be adapted to answer the question.

Close collaboration between the health economist and the rest of the GDG is essential early in the guideline development process to ensure that:

  • the most important questions are selected for economic analysis

  • the overall methodological approach is appropriate

  • all of the important health effects and resource costs are included

  • the clinical, epidemiological and resource evidence used is the best available and the assumptions are plausible

  • the results of the analysis are interpreted appropriately and the limitations acknowledged.

It is acknowledged that the NCC has limited resources and time to construct new economic analyses. Therefore the complexity and number of new analyses will vary depending on what are considered priority areas and what information is required for robust decision making.

Economic analysis is potentially useful for any question in which one intervention or service is compared with another. This includes comparisons of methods for prevention, screening, risk assessment, diagnosis, monitoring, rehabilitation and follow-up, as well as treatment. It may also be appropriate for comparisons of different combinations or sequences of interventions, as well as individual components of the patient management algorithm. However, given the broad scope of many clinical guidelines, it will not be possible to conduct original analyses for every component. Selecting questions for further economic analysis, including modelling, should be a joint decision between the health economist and the other GDG members. Selection should be based on systematic consideration of the potential value of economic analysis across all key clinical issues.

An economic analysis will be more useful if it is likely to influence a recommendation, and if the health and financial consequences of the recommendation are large. The value of an economic analysis thus depends on:

  • the overall 'importance' of the recommendation (which is a function of the number of patients affected and the potential impact on costs and health outcomes per patient)

  • the current extent of uncertainty over cost effectiveness, and the likelihood that economic analysis will reduce this uncertainty.

For a particular question, new economic analyses may not be warranted if, for example, the clinical evidence is so uncertain that it is not possible to give even a rough estimate of cost effectiveness. Alternatively, the published evidence on cost effectiveness may be so reliable that further economic analysis would be superfluous. Economic analysis may also not be a priority if it is obvious that the resource implications are modest in relation to the expected health gains.

7.2 Modelling approaches

Economic evaluation will usually be conducted in the form of a cost-effectiveness analysis, with the health effects being measured using an appropriate non-monetary outcome indicator. In circumstances for which cost-effectiveness analysis is not appropriate, other validated methods may be used.

Cost-effectiveness analysis with the units of effectiveness expressed in cost per QALY gained (cost–utility analysis) is widely recognised as a useful approach for measuring and comparing the efficiency of different health interventions. QALYs are an overall measure of health outcome that weight the life expectancy of a patient with an estimate of their HRQoL (measured on a 0–1 scale). There are well documented methodological problems with QALYs, but this is also true of other approaches. The NICE technology appraisal programme (see section 8.1) uses the QALY approach. If suitable data are available, this approach should also be followed in clinical guideline development. If there are not sufficient data to estimate QALYs gained, an alternative measure of effectiveness may be considered for the cost-effectiveness analysis (such as life years gained or cases averted, or a more disease-specific outcome).

A cost-effectiveness analysis could be modelled around a single well-conducted randomised controlled trial, or by using decision-analytic techniques with probability, cost and health outcome data from a variety of published sources. For clinical guidelines there is often a trade-off between the range of new analyses that the health economist can conduct and the complexity of each piece of analysis. Simple methods may be used if these can provide the GDG with sufficient information on which to base a decision. For example, if an intervention is associated with better health outcomes and fewer adverse effects, then an estimate of cost may be all that is needed. Or a simple decision tree may provide a sufficiently reliable estimate of cost effectiveness. In other situations a more complex approach, such as Markov modelling or discrete event simulation, may be warranted.

Specific guidance on methods of cost-effectiveness analysis can be found in NICE's Guide to the methods of technology appraisal. This includes a 'reference case', which specifies the methods considered by NICE to be the most appropriate for technology appraisals, and which is consistent with the NHS objective of maximising health gain from limited resources (see table 7.1). Economic analyses conducted for NICE clinical guidelines should usually follow this same reference case. Departures from the reference case may sometimes be appropriate in clinical guidelines, for example when there are insufficient data to estimate QALYs gained. Any such departures must be highlighted in the full guideline and reasons given. Advice on how to implement the approaches described in NICE's Guide to the methods of technology appraisal is provided by the technical support documents developed by the NICE Decision Support Unit (DSU).

For the reference case, the perspective on outcomes should be all direct health effects on individuals, whether they are patients or others (principally carers). The perspective on costs should be that of the NHS and PSS. Some interventions or services may have a substantial impact on non-health outcomes or costs to other government bodies (for example, treatments to reduce illicit drug misuse may have the effect of reducing drug-related crime). Costs to other government bodies may be included if this has been specifically agreed with the Department of Health, usually before the referral of the topic. When non-reference-case analyses include these broader costs, explicit valuation methods are required. In all cases, these costs should be reported separately from the NHS and PSS costs. These costs should not be combined into an incremental cost-effectiveness ratio (ICER; where the QALY is the outcome measure of interest).

Productivity costs and costs borne by patients and carers that are not reimbursed by the NHS or social services should not usually be included in any analyses (see the Guide to the methods of technology appraisal).

The Guide to the methods of technology appraisal and accompanying technical support documents include other useful advice for health economists who are developing economic analyses for use in clinical guidelines.

Table 7.1 Summary of the reference case

This table is adapted from the consultation version of the NICE Guide to the methods of technology appraisal, which is currently being updated (publication expected spring 2013).

Element of health technology assessment

Reference case

Defining the decision problem

The scope developed by NICE

Comparator

Interventions routinely used in the NHS, including those regarded as current best practice

Perspective on outcomes

All direct health effects, whether for patients or, when relevant, other people (principally family members or informal carers)

Perspective on costs

NHS and PSS

Type of economic evaluation

Cost–utility analysis with fully incremental analysis

Time horizon

Long enough to reflect all important differences in costs or outcomes between the technologies being compared

Synthesis of evidence on health effects

Based on a systematic review

Measuring and valuing health effects

Health effects should be expressed in QALYs. The EQ-5D is the preferred measure of HRQoL in adults.

Source of data for measurement of HRQoL

Reported directly by patients and/or carers

Source of preference data for valuation of changes in HRQoL

Representative sample of the UK population

Equity considerations

An additional QALY has the same weight regardless of the other characteristics of the people receiving the health benefit

Evidence on resource use and costs

Costs should relate to NHS and PSS resources and should be valued using the prices relevant to the NHS and PSS

Discounting

The same annual rate for both costs and health effects (currently 3.5%)

HRQoL, health-related quality of life; PSS, personal social services; QALY, quality-adjusted life year.

7.2.1 General principles

Regardless of the methodological approach taken, the general principles described below should be observed. The health economist should carry out each economic analysis in collaboration with the rest of the GDG. Any variation from the principles outlined below should be described and justified in the economic analysis.

Economic analyses should be explicitly based on the guideline's review questions. The economic analysis should compare all relevant alternatives for specified groups of patients. Any differences between the review question(s) and the economic analysis should be clearly acknowledged, justified and explained, with the approval of the GDG. The interventions or services included in the analysis should be described in sufficient detail to allow stakeholders to understand exactly what is being assessed. This is particularly important when calculating the cost effectiveness of services.

An economic analysis should be underpinned by the best-quality clinical evidence. The evidence should be based upon and consistent with that identified in addressing the guideline's review question. Sometimes the systematic reviewer will not have time to conduct an analysis (for example, a meta-analysis) for a key model parameter; in this case the health economist may conduct the analysis in collaboration with the rest of the GDG and NCC team. If clinical opinion is used in the cost-effectiveness analysis, this should be clearly stated and justified in the full guideline.

If existing models are being used or are informing the new analyses, the process of how these studies are being adapted or used to inform the new analyses should be outlined clearly.

The structure of the model should be discussed and agreed with the GDG early in development. Potential alternatives should be identified and considered for structural sensitivity analysis.

All cost-effectiveness analyses should be validated. The validation process should be outlined in the full guideline. Useful and practical validation methods could include:

  • systematic checking of model formulae and inputs by a second modeller

  • one-way and n-way sensitivity analyses (including null values and extreme values) (Krahn et al. 1997)

  • ensuring that the model results are plausible and can be explained

  • comparing clinical end points from the model with source materials.

If analyses are conducted to demonstrate external validity, the results should be reported. However, relevant data should not be omitted from inclusion to facilitate external validation (for example, not including clinical trials so that they can be used for subsequent validation).

There should be the highest level of transparency in reporting methods and results. Conventions on reporting economic evaluations should be followed (see Drummond and Jefferson 1996). In particular, the following results should be presented:

  • clinical end points from the analysis, such as life years gained, number of events and survival

  • disaggregated costs

  • total and incremental costs and QALYs for all options.

When comparing multiple mutually exclusive options, a fully incremental approach should be adopted that compares the treatments sequentially in rank order of effectiveness (or cost). Comparisons with a common baseline should not be used for decision-making.

7.2.2 Exploring uncertainty

Considerations of potential bias and limitations should be discussed by the GDG. Sensitivity analysis should be used to explore the impact of potential sources of bias and uncertainty on the results of the economic analysis.

Probabilistic sensitivity analysis is the preferred method for taking account of uncertainty arising from imprecision in model parameters. It allows the uncertainty associated with different parameters to be reflected simultaneously in the model results. Probabilistic methods also provide the best estimates of mean costs and outcomes in non-linear decision models where outputs are a result of a multiplicative function (for example, in Markov models). The choice of distributions used should be justified; for example, in relation to the available evidence or published literature. Options for presentation of the results of probabilistic sensitivity analysis include scatter plots and cost-effectiveness acceptability curves and frontiers.

If the health economist decides not to use probabilistic methods, this should be clearly stated and justified in the full guideline. The impact of parameter uncertainty should be thoroughly explored using deterministic sensitivity analysis.

Potential bias resulting from key structural assumptions should be explored through deterministic sensitivity analyses, which test whether and how the model results in change under alternative plausible scenarios. Common examples of when this type of sensitivity analysis could be conducted are:

  • when there is uncertainty about the most appropriate assumption to use for extrapolation of costs and outcomes beyond the trial follow-up period

  • when there is uncertainty about how the pathway of care is most appropriately represented in the analysis

  • when there may be economies of scale (for example, when appraising diagnostic technologies).

Deterministic sensitivity analysis should also be used to test the impact of potential bias resulting from the selection or exclusion of data sources for key model parameters.

Consideration can be given to including structural assumptions and the inclusion or exclusion of data sources in probabilistic sensitivity analysis. In this case the method used to select the distribution should be outlined in the full guideline (Jackson et al. 2011).

7.2.3 Identification and selection of model inputs

The NICE reference case (table 7.1) states that evidence on health effects should be obtained from a systematic review. Although it is desirable to conduct systematic literature reviews for other model inputs, this is time-consuming, and there is an opportunity cost in terms of both the health economist's and the information specialist's time. Therefore, before requesting additional literature searches from the information specialist, the health economist should explore pragmatic options for identifying inputs for economic analyses. This could include liaising with the systematic reviewer about using data from the studies identified in the clinical review. Alternatives could include asking GDG members and other experts for suitable papers or eliciting their opinions. If an additional literature search is necessary, the health economist should discuss this with the information specialist. If longer-term follow-up data are required, a literature search to identify cohort studies may be appropriate. It has been suggested (Cooper et al. 2007) that other search methods may be more efficient for identifying information for economic models. The report by Philips and co-workers (2004) is a useful guide to searching methods for economic models. When a systematic review is not possible, the health economist should use transparent processes for identifying other possible model inputs, assure their quality and justify their inclusion or exclusion.

Information on unit costs should be routinely obtained from national list prices such as the NHS drug tariff, the PSSRU (Personal Social Services Research Unit) Unit costs of health and social care or Department of Health reference costs. Information on costing can also be found in NICE's Assessing cost impact: methods guide and through discussion with the NICE costing analyst for the guideline. Some information about epidemiology or health service use might be better obtained from national statistics or databases than from studies in the literature.

As outlined in the updated NICE Guide to the methods of technology appraisal (publication expected spring 2013), the public list prices for technologies (for example, pharmaceuticals or medical devices) should be used in the reference-case analysis. When there are nationally available price reductions, for example for drugs procured for use in secondary care through contracts negotiated by the NHS Commercial Medicines Unit, the reduced price should be used in the reference-case analysis to best reflect the price relevant to the NHS. The Commercial Medicines Unit publishes information on the prices paid for some generic drugs by NHS trusts through its Electronic Market Information Tool (eMIT), focusing on drugs in the 'National Generics Programme Framework' for England. Analyses based on price reductions for the NHS will be considered only when the reduced prices are transparent and can be consistently available across the NHS, and if the period for which the specified price is available is guaranteed. When a reduced price is available through a patient access scheme that has been agreed with the Department of Health, the analyses should include the costs associated with the scheme. The health economist from the NCC is also encouraged to discuss the analyses with the appraisals team in the Centre for Health Technology Evaluation at NICE. For drugs that are predominantly prescribed in primary care, prices should be based on the Drug Tariff. In the absence of a published list price and a price agreed by a national institution (as may be the case for some devices), an alternative price may be considered, provided that it is nationally and publicly available.

HRQoL data are often needed for economic models. Many of the HRQoL search filters available are highly sensitive and so, although they identify relevant literature, they also detect a large amount of irrelevant literature. An initial broad HRQoL literature search may be a good option, but the amount of information identified may be unmanageable (depending on the key clinical issue being addressed). It may be more appropriate and manageable to incorporate a HRQoL search filter when executing additional searches for key clinical issues of high economic priority. The provision of HRQoL data should be guided by the health economist at an early stage in the guideline development process so that the information specialist can adopt an appropriate strategy. Two resources for identifying useful sources of utility data for economic modelling are the database of preference weights on the CEA (Cost-Effectiveness Analysis) Registry website and the NICE Decision Support Unit technical support document The identification, review and synthesis of health state utility values from the literature.

7.3 Economic evidence and guideline recommendations

For an economic analysis to be useful, it must inform the guideline recommendations. Cost effectiveness and clinical effectiveness should be discussed in parallel when formulating recommendations.

If there is strong evidence that one clinical strategy 'dominates' the alternatives (that is, it is both more effective and less costly), clearly this strategy should be recommended for appropriate patients. However, if, as is often the case, one strategy is more effective but also more costly, then the magnitude of the ICER should be considered. For example, the cost per QALY gained is calculated as the difference in mean cost divided by the difference in mean QALYs for one strategy compared with the next most effective alternative strategy.

If one intervention appears to be more effective than another, the GDG will have to decide whether the increase in cost associated with the increase in effectiveness represents reasonable 'value for money'. In doing so, it should make reference to the principles outlined in NICE's report Social value judgements: principles for the development of NICE guidance. This states the following:

'NICE has never identified an ICER above which interventions should not be recommended and below which they should. However, in general, interventions with an ICER of less than £20,000 per QALY gained are considered to be cost effective. Where advisory bodies consider that particular interventions with an ICER of less than £20,000 per QALY gained should not be provided by the NHS they should provide explicit reasons (for example that there are significant limitations to the generalisability of the evidence for effectiveness). Above a most plausible ICER of £20,000 per QALY gained, judgements about the acceptability of the intervention as an effective use of NHS resources will specifically take account of the following factors.

  • The degree of certainty around the ICER. In particular, advisory bodies will be more cautious about recommending a technology when they are less certain about the ICERs presented in the cost-effectiveness analysis.

  • The presence of strong reasons indicating that the assessment of the change in the quality of life is inadequately captured, and may therefore misrepresent, the health gain.

  • When the intervention is an innovation that adds demonstrable and distinct substantial benefits that may not have been adequately captured in the measurement of health gain.

As the ICER of an intervention increases in the £20,000 to £30,000 range, an advisory body's judgement about its acceptability as an effective use of NHS resources should make explicit reference to the relevant factors considered above. Above a most plausible ICER of £30,000 per QALY gained, advisory bodies will need to make an increasingly stronger case for supporting the intervention as an effective use of NHS resources with respect to the factors considered above.'

The Guide to the methods of technology appraisal outlines additional considerations that GDGs should take into account when developing recommendations. These include when to conduct a sensitivity analysis on the discount rate, and special considerations when examining a 'life-extending treatment at the end of life'.

The GDG's interpretations and discussions should be clearly presented in the 'Evidence to recommendations' sections of the full guideline. This should include a discussion of potential sources of bias and uncertainty. It should also include the results of sensitivity analyses in the consideration of uncertainty, as well as any additional considerations that are thought to be relevant.

7.3.1 In the absence of cost-effectiveness evidence

When no relevant published studies are found, and a new economic analysis is not prioritised, the GDG should make a qualitative judgement about cost effectiveness by considering potential differences in resource use and cost between the options alongside the results of the review of evidence of clinical effectiveness. The health economist should help the GDG to come to conclusions on the potential cost effectiveness of the interventions or services under consideration. This may include presenting information about unit costs and economic principles.

7.4 Further reading

Anderson R (2010) Systematic reviews of economic evaluations: utility or futility? Health Economics 19: 350–64

Briggs A, Claxton K, Sculpher K (2006) Decision modelling for health economic evaluation. Oxford: Oxford University Press

Centre for Reviews and Dissemination (2007) NHS economic evaluation database handbook [online].

Cooper NJ, Sutton AJ, Ades AE et al. (2007) Use of evidence in economic decision models: practical issues and methodological challenges. Health Economics 16: 1277–86

Drummond MF, Jefferson TO (1996) Guidelines for authors and peer reviewers of economic submissions to the BMJ. British Medical Journal 313: 275–83

Drummond MF, McGuire A (2001) Economic evaluation in health care: merging theory with practice. Oxford: Oxford University Press

Drummond MF, Sculpher MJ, Torrance GW et al. (2005) Methods for the economic evaluation of health care programmes, 3rd edition. Oxford: Oxford University Press

Eccles M, Mason J (2001) How to develop cost-conscious guidelines. Health Technology Assessment 5: 1–69

Jackson CH, Bojke L, Thompson G et al. (2011) A framework for addressing structural uncertainty in decision models. Medical Decision Making 31: 662–74

Krahn MD, Naglie G, Naimark D et al. (1997) Primer on medical decision analysis: Part 4 – Analyzing the model and interpreting the results. Medical Decision Making 17: 142–51

NICE Decision Support Unit (2011) Technical support document series [online]

Philips Z, Ginnelly L, Sculpher M et al. (2004) Review of good practice in decision-analytic modelling in health technology assessment. Health Technology Assessment 8: 1–158

Raftery J, editor (1999–2001) Economics notes series. British Medical Journal [online]



[11] Information throughout this manual relating to the role of the National Collaborating Centres in guideline development also applies to the Internal Clinical Guidelines Programme at NICE.

[12] Department of Health definition: PSS – personal social services describes care services for vulnerable people, including those with special needs because of old age or physical disability and children in need of care and protection. Examples are residential care homes for the elderly, home help and home care services, and social workers who provide help and support for a wide range of people.