It is often difficult to determine what actually was done in work involving data collected with stated preference surveys because the terms used to describe various procedures have ambiguous and ...sometimes conflicting meanings. Further, terms used to describe data collection procedures often are confounded with terms used to describe statistical techniques. We call for the use of a common nomenclature to describe what was done in a data collection effort for stated preference studies, and take a first step at setting out such nomenclature. We only seek to improve clarity in the communication of research results and take no position here on appropriateness of particular procedures.
We review the measurement of product attribute importance, and find little consensus in definition or measurement methods. We compare four measurement methods: 1) two direct methods whereby ...respondents report the importance of attributes using best–worst scaling or constant sum scales, and 2) two indirect methods derived from discrete choice experiments. Our comparisons rely on previous findings that choice experiments are externally valid to use as the standard. We find high agreement within direct or indirect methods, but less agreement between direct and indirect methods. Our results also demonstrate that inferences derived from indirect measures appear to be susceptible to context effects related to the particular attributes a researcher chooses to investigate. We discuss implications for current and future research.
We present an experiment designed to investigate the presence and nature of ordering effects within repeat-response stated preference (SP) studies. Our experiment takes the form of a large sample, ...full-factorial, discrete choice SP exercise investigating preferences for tap water quality improvements. Our study simultaneously investigates a variety of different forms of position-dependent and precedent-dependent ordering effect in preferences for attributes and options and in response randomness. We also examine whether advanced disclosure of the choice tasks impacts on the probability of exhibiting ordering effects of those different types. We analyze our data both non-parametrically and parametrically and find robust evidence for ordering effects. We also find that the patterns of order effect in respondents' preferences are significantly changed but not eradicated by the advanced disclosure of choice tasks a finding that offers insights into the choice behaviors underpinning order effects.
In discrete choice experiments, design decisions are crucial for determining data quality and costs. While high statistical efficiency designs are desirable, they may come at a price if they increase ...the cognitive burden for respondents. We address this problem by designing 44 experiments that systematically vary numbers of attributes and attribute level differences. Our results for two product categories suggest that respondents systematically are less consistent in answering choice questions as statistical efficiency increases. This relationship holds regardless of the number of attributes and is statistically significant even if one accommodates preference heterogeneity. Implications for practice and future research are discussed.
This paper reports the first application of the capabilities approach to the development and valuation of an instrument for use in the economic evaluation of health and social care interventions. The ...ICECAP index of capability for older people focuses on quality of life rather than health or other influences on quality of life, and is intended to be used in decision making across health and social care in the UK. The measure draws on previous qualitative work in which five conceptual attributes were developed: attachment, security, role, enjoyment and control. This paper details the innovative use within health economics of further iterative qualitative work in the UK among 19 informants to refine lay terminology for each of the attributes and levels of attributes used in the eventual index. For the first time within quality of life measurement for economic evaluation, a best-worst scaling exercise has been used to estimate general population values (albeit for the population of those aged 65+ years) for the levels of attributes, with values anchored at one for full capability and zero for no capability. Death was assumed to be a state in which there is no capability. The values obtained indicate that attachment is the attribute with greatest impact but all attributes contribute to the total estimation of capability. Values that were estimated are feasible for use in practical applications of the index to measure the impact of health and social care interventions.
Statements like “quality of care is more highly valued than waiting time” can neither be supported nor refuted by comparisons of utility parameters from a traditional discrete choice experiment ...(DCE). Best–worst scaling can overcome this problem because it asks respondents to perform a different choice task. However, whilst the nature of the best–worst task is generally understood, there are a number of issues relating to the design and analysis of a best–worst choice experiment that require further exposition. This paper illustrates how to aggregate and analyse such data and using a quality of life pilot study demonstrates how richer insights can be drawn by the use of best–worst tasks.
Health services researchers are increasingly using discrete choice experiments (DCEs) to model a latent variable, be it health, health-related quality of life or utility. Unfortunately it is not ...widely recognised that failure to model variance heterogeneity correctly leads to bias in the point estimates. This paper compares variance heterogeneity latent class models with traditional multinomial logistic (MNL) regression models. Using the ICECAP-O quality of life instrument which was designed to provide a set of preference-based general quality of life tariffs for the UK population aged 65+, it demonstrates that there is both mean and variance heterogeneity in preferences for quality of life, which covariate-adjusted MNL is incapable of separating. Two policy-relevant mean groups were found: one group that particularly disliked impairments to independence was dominated by females living alone (typically widows). Males who live alone (often widowers) did not display a preference for independence, but instead showed a strong aversion to social isolation, as did older people (of either sex) who lived with a spouse. Approximately 6–10% of respondents can be classified into a third group that often misunderstood the task. Having a qualification of any type and higher quality of life was associated with smaller random component variances. This illustrates how better understanding of random utility theory enables richer inferences to be drawn from discrete choice experiments. The methods have relevance for all health studies using discrete choice tasks to make inferences about a latent scale, particular QALY valuation exercises that use DCEs, best-worst scaling and ranking tasks.
In this paper we compare a number of common strategies for constructing discrete choice experiments. Two of the strategies, including one based on theoretical constructions for optimal discrete ...choice experiments, produce designs that are better than those that come about from random grouping and from using the L
MA construction. A simple account of this theoretical construction is given.
Many empirical examinations of foreign direct investment location choice have relied on the use of secondary data and surveys on the choices made by firms about the form and location of overseas ...investment. These studies have two inherent and related problems. First, they rely solely on the location choices made by different firms, and assume that the domains of possible options considered were the same. Second, there is an assumption about the rules used by firms to make these decisions, yet the decisions are made by boundedly rational managers. After reviewing the literature, this study examines managers' choices about foreign investment location through the use of structured experimentation. The results show that in creating sets of investments to 'consider', managers appear to follow fairly rational rules. However, the choice of actual 'investments' appears less aligned to traditional models.
This study uses best-worst scaling experiments to examine differences across six countries in the attitudes of consumers towards social and ethical issues that included both product related issues ...(such as recycled packaging) and general social factors (such as human rights). The experiments were conducted using over 600 respondents from Germany, Spain, Turkey, USA, India, and Korea. The results show that there is indeed some variation in the attitudes towards social and ethical issues across these six countries. However, what is more telling are the similarities seen and the extent to which individual variation dominates observable demographics and country-based variables.
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