Emma McIntosh

Methodological issues in the application of conjoint analysis in health care

This paper adds to an increasing literature on methodological questions addressed in the application of conjoint analysis (CA) in health care. Three issues are addressed: ordering effects; internal validity; and internal consistency. The results of an application of CA in a primary care setting provide no evidence that the ordering of scenarios was important. Evidence was found of both internal validity and internal consistency. In addition, individual preferences were found to be determined by experiences, which raise potentially important questions regarding the elicitation and use of such preferences in economic evaluation.

Role of home visiting in improving parenting and health in families at risk of abuse and neglect: results of a multicentre randomised controlled trial and economic evaluation

Objectives: To evaluate the effectiveness and cost effectiveness of an intensive home visiting programme in improving outcomes for vulnerable families. Design: Multicentre randomised controlled trial in which eligible women were allocated to receive home visiting (n = 67) or standard services (n = 64). Incremental cost analysis. Setting: 40 general practitioner practices across 2 counties in the UK. Participants: 131 vulnerable pregnant women. Intervention: Selected health visitors were trained in the Family Partnership Model to provide a weekly home visiting service from 6 months antenatally to 12 months postnatally. Main outcome measures: Mother–child interaction, maternal psychological health attitudes and behaviour, infant functioning and development, and risk of neglect or abuse. Results: At 12 months, differences favouring the home-visited group were observed on an independent assessment of maternal sensitivity (p<0.04) and infant cooperativeness (p<0.02). No differences were identified on any other measures. A non-significant increase in the likelihood of intervention group infants being the subject of child protection proceedings, or being removed from the home, and one death in the control group were found. The mean incremental cost per infant of the home visiting intervention was £3246 (bootstrapped 95% CI for the difference £1645–4803). Conclusion: This intervention may have the potential to improve parenting and increase the identification of infants at risk of abuse and neglect in vulnerable families. Further investigation is needed, along with long-term follow-up to assess possible sleeper effects.

Using discrete choice experiments to derive welfare estimates for the provision of elective surgery: Implications of discontinuous preferences

The estimation of a discrete choice experiment model complying with consumer theory axioms allows estimation of the welfare implications of alternative policies. Such a normative approach anchors the results of discrete choice experiments within a welfare economics framework. Where cost is included in the design, compensating variation can be estimated, permitting the use of the results directly within cost–benefit analysis. Any assumptions made about compliance with axioms however directly impact upon the welfare estimates derived from discrete choice experiments. Hence if discrete choice experiments are to be used to estimate welfare within health care, it is important that issues surrounding adherence to these axioms are explored. The study showed that a significant proportion of the sample did not comply with the axioms of continuity and transitivity, as defined by the specific tests used. This study compares welfare estimates obtained from continuous preferences with those which appear to be discontinuous. The results raise questions about how discrete choice experiment derived preferences should be incorporated into a traditional welfare economics framework.

A framework for the economic evaluation of telemedicine.

This paper describes the economic issues associated with the introduction of telemedicine systems and the main challenges to their evaluation. An approach to the economic evaluation of telemedicine is described based on a cost-consequence framework. The paper links these costs and consequences more formally within a set of evaluative questions which in turn forms the basis for an economic model for evaluating telemedicine. By outlining the key questions, a number of issues relevant to the evaluation of telemedicine are identified and considered. The main challenges to the economic evaluation of telemedicine include: constantly changing technology; lack of appropriate study design to manage the frequently inadequate sample sizes; inappropriateness of the conventional techniques of economic evaluation; and the valuation of health and non-health outcomes. The present study addresses these challenges and suggests ways of advancing the techniques for the economic evaluation of telemedicine.

Applying conjoint analysis in economic evaluations: an application to menorrhagia

The increased demand for health care, coupled with limited resources, means that decisions have to be made concerning the allocation of scarce health care resources. This paper considers how conjoint analysis (CA) can be used to aid this decision making process. It is shown how the technique can be used to estimate marginal rates of substitution between attributes, willingness to pay (WTP) if cost is included as an attribute and overall utility scores for different ways of providing a service. The technique is applied to consider womens preferences for two surgical procedures in the treatment of menorrhagia: hysterectomy and conservative surgery. The results suggest conservative surgery is preferred to hysterectomy, as indicated by higher utility scores for the former and a marginal WTP of 7593 to have conservative surgery rather than hysterectomy. The internal validity of CA was also shown. It is concluded that CA is a potentially useful instrument for policy makers. However, numerous methodological issues need addressing before the technique becomes an established instrument within economic evaluations.

Recent advances in the methods of cost-benefit analysis in healthcare. Matching the art to the science.

This paper outlines recent advances in the methods of cost-benefit analysis (CBA). Economic evaluations in healthcare can be criticised for, amongst other things, the inappropriate use of incremental cost-effectiveness ratios and the reporting of benefits in terms of cost savings, such as treatment costs averted. Many such economic evaluations are, according to the ‘scientific’ definition, CBAs. The ‘balance-sheet’ (or opportunity cost) approach is a form of CBA which can be used to identify who bears the costs and who reaps the benefits from any change. Whilst the next stage in a CBA, as defined in health economics, would require that all costs and benefits be valued in monetary terms, the balance-sheet approach, however, advocates that available monetary values can be augmented by other measures of cost and benefit. As such, this approach, which has a theoretical basis, is proposed as a practical prescription for CBA and highlights the notion that unquantified benefits are important and can be included within CBAs even when monetarisation is not possible.Recent methodological developments in monetary valuation for use in CBA are the development of the technique of willingness to pay, the use of conjoint analysis (CA) to elicit willingness-to-pay (WTP) values and advances in the debate on the inclusion of production gains in CBAs. Whilst acknowledging that there have been developments in each of these areas, it is claimed there has also been progress in using CBA as a framework for evaluation, as reflected by the balance-sheet approach.The paper concludes by stating that almost all types of economic evaluation have an element of the ‘cost-benefit’ approach in them. The important issue is to focus on the policy question to be addressed and to outline the relevant costs and benefits in a manner which assists the evaluation of welfare changes resulting from changes in healthcare delivery. The focus should not be on moulding a question to fit a hybrid definition of an analytical technique.

The importance of drug adverse effects compared with seizure control for people with epilepsy: a discrete choice experiment.

AbstractIntroduction: Antiepileptic drugs (AEDs) have been shown to reduce the severity and frequency of seizures for most patients. However, many patients experience adverse effects in order to maintain seizure control. Study design: A stated preference discrete choice experiment (DCE) was used to explore the preferences of people with epilepsy regarding the adverse effects and seizure control of AEDs. Methods: The main adverse effects of AEDs were identified through a literature search and expert consultation. In addition, a national epilepsy patient advocacy group helped to identify important attributes and commented on the attributes we had already identified. The DCE included five attributes related to adverse effects (alopecia, nausea, skin rash, concentration effects and weight change) plus seizure control and cost (to estimate willingness to pay [WTP]). A cost attribute was included in the DCE in order to estimate people’s WTP for changes in attribute levels.Five hundred members of a national patient advocacy group with a diagnosis of epilepsy were presented with pairs of hypothetical drug profiles with varied levels of adverse effects, seizure control and cost; they were then asked to indicate which drug they preferred. Questions were also included to collect sociodemographic data (including income) and information regarding experience of adverse effects and medication. The survey was administered via the post and the Internet. Data were analysed using a random effects probit model. Results: A total of 148 surveys were returned. All attributes were significant and had the expected polarity, i.e. participants showed a preference for less severe adverse effects, greater seizure control and less cost. To achieve 100% seizure control and no adverse effects, participants were willing to pay £709 (

Oxygen saturation targets in infants with bronchiolitis (BIDS): a double-blind, randomised, equivalence trial

US1105) per month, 95% CI £451, £1278 (£1 =

Using discrete choice experiments within a cost-benefit analysis framework: some considerations.

US1.56, 2002 exchange rate). Participants’ WTP was significantly influenced by different adverse effects; for example, people with epilepsy were willing to pay only £174 (

Using conjoint analysis to elicit the views of health service users: an application to the patient health card

US271) per month for a drug that provided seizure freedom but also caused hair loss. Segmented models showed that seizure frequency has a significant negative impact on respondents’ income levels. Also, women were willing to pay twice as much as men to avoid weight gain. Participants were also willing to trade changes in seizure control for improvements in adverse effects. Conclusion: Participants placed a high value on gaining total seizure control with no adverse effects. This study underlines the importance that people with epilepsy place on reducing adverse effects. The study also revealed how preferences for AEDs vary in different subgroups. Management of epilepsy is usually aimed at minimising seizures within a tolerable level of adverse effects. The present study suggests that people with epilepsy have strong preferences for reducing adverse effects as well as improving seizure control. These data may be considered useful when making medical management decisions in epilepsy.