Conjoint Preference Elicitation Methods in the Broader Context of Random Utility Theory Preferenc... more Conjoint Preference Elicitation Methods in the Broader Context of Random Utility Theory Preference Elicitation Methods Hensher, Louviere & Swait 2 but some are not, some methods permit one to combine experimental with actual marketplace choice data but many do not, etc. Indeed, there are many ways to understand and model preferences and choices, some of which bear scant relation to one another and others that are incompatible, both theoretically and analytically. RUT offers a way to unify many seemingly disparate approaches to understand and model preference formation and choice. Figure represents an overview of the general problems covered by RUT, which can assist our understanding of the role of conjoint analysis methods within RUT. Figure should be regarded as a pedagogical vehicle to help explain why a more general view is required; it is not a theory per se.
Mixtures of revealed preference and stated preference data are recognised by transportation resea... more Mixtures of revealed preference and stated preference data are recognised by transportation researchers as offering a richness of behavioural input to travel choice modelling that is often absent from the isolated use of each data source. Accumulating evidence from various literatures, especially in marketing, psychology and transportation, provides support for the desirability of combining sources of preference data as a way of transferring increasing power of understanding of travel behaviour from the econometrics of a model to the underlying data inputs. Together with advances in the specification and estimation of discrete choice models, we are beginning to see that the simpler choice models such as multinomial logit (MNL) deliver an amazing amount of behavioural power providing that the underlying data specification is given a statistically rigorous treatment. There still remains however a growing role for more general choice models as a way of establishing the relevance of the simpler MNL model. This paper reviews the major contributions to the literature on combining sources of preference data and suggests new directions for fruitful research.
Transportation Research Part B-methodological, Apr 1, 2019
Discrete choice studies, with rare exception, assume that agents act as if sources of observed ut... more Discrete choice studies, with rare exception, assume that agents act as if sources of observed utility are captured through a linear in parameters and additive in attributes (LPAA) form, with some interactions. A growing number of transport (and other) choice studies have investigated one or more alternative processing rules adopted by agents in arriving at a choice, raising interest in how best to represent the utility expressions in a joint process and outcome choice model. Given the popular and appealing random parameter treatment of LPAA in mixed logit as a way of identifying non-systematic preference heterogeneity in a sample, this paper considers the possibility that we might be able to interact specific process heuristics with LPAA to uncover sources of systematic preference heterogeneity hidden in the standard LPAA form, and hence establish a link between the LPAA form and candidate process heuristics, offering a way to embellish and hence clarify the contributions to preference heterogeneity attributable to the presence of process heterogeneity. Specifically, we are interested in the extent to which there is a systematic relationship between the simple LPAA form and the more complex (albeit behaviourally realistic) process heuristics emerging in the transport literature which we call conditioning by random process heterogeneity (CRPH). In this paper, in addition to LPAA, we consider two process heuristics -Value Learning, and Relative Advantage Maximisation -with an overlay to account for risk attitudes, perceptual conditioning, and overt experience. The findings, using two data sets, suggest that empirically there exists a significant attribute-specific relationship between preference heterogeneity identified through specific process heuristics and through the LPAA assumption. How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins 1 How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins
Transportation Research Part B-methodological, Jul 1, 2010
With the growing reliance on Stated Choice (SC) data, researchers are increasingly interested in ... more With the growing reliance on Stated Choice (SC) data, researchers are increasingly interested in understanding how respondents process the information presented to them in such surveys. Specifically, it has been argued that some respondents may simplify the choice tasks by consistently ignoring one or more of the attributes describing the alternatives, and direct questions put to respondents after the completion of SC surveys support this hypothesis. However, in the general context of issues with response quality in SC data, there are certainly grounds for questioning the reliability of stated attribute processing strategies. In this paper, we take a different approach by attempting to infer attribute processing strategies through the analysis of respondent-specific coefficient distributions obtained through conditioning on observed choices. Our results suggest that a share of respondents do indeed ignore a subset of explanatory variables. However, there is also some evidence that the inferred attribute processing strategies are not necessarily consistent with the stated attribute processing strategies. Additionally, there is some evidence that respondents who claim to have ignored a certain attribute may simply have assigned it lesser importance. The results produced by the inferring approach not only lead to slightly better fit but also more consistent results.
In recent years we have seen an explosion of research seeking to understand the role that rules a... more In recent years we have seen an explosion of research seeking to understand the role that rules and heuristics might play in improving the predictive capability of discrete choice models, as well as delivering willingness to pay estimates for specic attributes that may (and often do) dier signicantly from estimates based on a model specication that assumes all attributes are relevant. This paper adds to that literature in one important way-it explicitly recognises the endogeneity issues raised by typical attribute non-attendance treatments and conditions attribute parameters on underlying unobserved attribute importance ratings. We develop a hybrid model system involving attribute processing and outcome choice models in which latent variables are introduced as explanatory variables in both parts of the model, explaining the answers to attribute processing questions and explaining heterogeneity in marginal sensitivities in the choice model. The resulting empirical model explains how lower latent attribute importance leads to a higher probability of indicating that an attribute was ignored or that it was ranked as less important, as well as increasing the probability of a reduced value for the associated marginal utility coecient in the choice model. The model does so by treating the answers to information processing questions as dependent rather than explanatory variables, hence avoiding potential risk of endogeneity bias and measurement error.
Individual's process the information in stated choice (SC) experiments in many different ways. In... more Individual's process the information in stated choice (SC) experiments in many different ways. In order to accommodate decisions rules that are used in processing information, there is good sense in conditioning the parameterisation of stated choice design attributes on these rules. In particular, rules might be invoked to cope with the dimensionality of the SC design. In this paper we investigate the impact of rules such as attribute aggregation and reference dependency on preference profiles for specific design attributes, as well as the design specification, as we vary the dimensionality of an SC design. Prior to identifying the empirical differences in valuation of travel time savings due to design specification, we account for scale differences from pooling 16 stated choice designs. The heteroscedastic extreme value logit model is estimated to identify the role of design dimensionality and attribute processing rules, after accounting for scale differences across the pooled data designs The empirical evidence, drawn from a study in Sydney of car commuter route choice, suggests that accounting for the way that stated choice designs are processed, given their dimensionality, does make a statistically significant difference on measures of willingness to pay, as does accounting for scale differences between pooled data designs. This evidence has value in guiding the design of SC experiments and in adjusting results from different SC designs when comparing the evidence.
According to neoclassical economic theory, the only stated preference elicitation format that can... more According to neoclassical economic theory, the only stated preference elicitation format that can feasibly be employed in field studies to which truthful response can be the dominant strategy for all respondents is a single binary choice between the status quo and one alternative. In studies where the objective is estimation of preferences for multiple attributes of a good, it is preferred (and, in some cases, necessary) based on econometric considerations, to present respondents with a sequence of choice tasks. Economic theory predicts that utility-maximising respondents may find it optimal to misrepresent their preferences in this elicitation format. In this paper, the effect on stated preferences of expanding the number of choice tasks per respondent from one to four is tested using a split sample treatment in an attribute-based survey relating to the undergrounding of overhead electricity and telecommunications wires in the Australian Capital Territory. We find evidence to sugge...
A dominant theme in the debate on road pricing reform is securing buy in from all key stakeholder... more A dominant theme in the debate on road pricing reform is securing buy in from all key stakeholders as a pre-condition for gaining support from politicians. This paper explores the key influences and the extent to which particular road pricing schemes are acceptable to the community at large, and how this translates into support if a scheme were subject to a vote in a referendum. Using data collected in Sydney in 2012 from a sample of car users, we estimate a recursive simultaneous bivariate probit model that recognises the endogeneity effect of scheme acceptability on voting plans. We find that there is a very strong link between voting intentions and scheme acceptability, and provide a series of direct elasticity estimates of the influence that the cost elements of road pricing reform schemes have on the joint probability of accepting and voting for a scheme.
Research in Transportation Business & Management, 2021
This paper explores whether the benefits from major urban transport spending increases are likely... more This paper explores whether the benefits from major urban transport spending increases are likely to differ greatly, depending on whether that spending prioritises light rail, a mode with growing interest and several new services recently developed in Australia, major road network improvement or provision of additional bus services. It does this through a series of case studies based on Sydney, using MetroScan, an integrated transport and land use strategic model system. MetroScan is the most sophisticated strategic integrated land use, transport and economic system evaluation model in Australia, with the capability of exploring dynamic interactions between transport improvements, residential locations and job locations, among other things. We specifically focus on the impacts of major transport initiatives on reducing risks that people will be socially excluded because of poor mobility opportunities.
Transportation Research Part A: Policy and Practice, 2016
Uncertainty of travel times and the impact on travel choice behavior has been recognized as an in... more Uncertainty of travel times and the impact on travel choice behavior has been recognized as an increasingly important research direction in the past decade. This paper proposes an extension to the popular scheduling approach to modeling traveler's departure time choice behavior under uncertainty, with the main focus on a richer representation of uncertainty. This more general approach incorporates a separate term to reflect the risk aversion associated with uncertainty. Recognizing the correlation between expected schedule delay and travel time variability, the schedule delay components in the generalized approach are defined in terms of expected travel time, which differs from the scheduling approach. This approach is developed based on the analytical investigation of the relationship between the expected schedule delay and the mean and standard deviation of travel time. An analytical equivalence was found between the scheduling approach and the general approach given a departure time t. To investigate the empirical performance of the generalized approach, two state preference (SP) data sets are used; one from China with a symmetric travel time distribution and the other from Australia with an asymmetric distribution. Both studies show empirical evidence of an equivalence in respect of statistical fit between the generalized and the scheduling approaches, as found from analytical investigations. The Chinese study gives support in the generalized model to including both the mean-variance and the scheduling effects; whereas the Australian study finds only the mean-variance specification has statistical merit. Despite the different travel contexts, it is noteworthy in both empirical settings, that the parameter estimate for arriving earlier than the preferred arrival time (PAT) in the generalized model is positive. This suggests that commuters tend to prefer to arrive earlier in order to guarantee he/she will not be late. This paper contributes to a better understanding of performances of different reliability measures and their relationships. The practical value of the various unreliability measures is provided showing that these indicators are easy to obtain for inclusion in project appraisal.
Decisions made by businesses on where to locate or relocate are typically given less consideratio... more Decisions made by businesses on where to locate or relocate are typically given less consideration than residential location in integrated transport and land use modelling systems. This is surprising given the important role that businesses play in defining employment opportunities, and hence the travel patterns of workers and any travel associated with accessing firms. As part of a larger study on giving firm location choices an endogenous representation in an integrated model system, this paper reviews the existing literature on the drivers of location and relocation decisions in various geographical jurisdictions. The findings provide a starting position in the design of future firm-specific surveys and especially the attributes that are candidates for stated choice experiments and for inclusion in firm location utility equations embedded in integrated strategic model systems.
Hensher, D.A. Data challenges: more behavioural and (relatively) less statistical, invited plenar... more Hensher, D.A. Data challenges: more behavioural and (relatively) less statistical, invited plenary paper for Elsevier
Transportation Research Part A: Policy and Practice, 2017
The digital age has opened up new opportunities to improve the customer experience in using publi... more The digital age has opened up new opportunities to improve the customer experience in using public transport. Specifically, we see the role of smart technology in the hands of customers as the new rubric to deliver services that are individualised to the needs and preferences of current and future public transport users. This frontline of service delivery has become known as mobility as a service (MaaS) whereby an individual can book a service delivered through a range of possible modes of transport. Variations are bus-based options that include smart bookable 'point-via-point-to-point' services that offer options on travel times and fares as well as the continuation of conventional bus services where the market for smart MaaS is difficult or inappropriate to provide (e.g., contracted (often free) school bus services). This paper presents a number of positions that could potentially represent future contexts in which bus services might be offered, recognising that a hybrid multi-modal state of affairs may be the most appealing new contract setting, enabling the design of contracts to be driven by the mode-neutral customer experience, and the growing opportunity to focus on MaaS. We suggest that the adrenal rush for mobility services, however, may not deliver the full solution that supporters are suggesting.
El presente artículo examina las múltiples dimensiones que el hacinamiento de pasajeros tiene en ... more El presente artículo examina las múltiples dimensiones que el hacinamiento de pasajeros tiene en la demanda, la oferta y las operaciones de transporte público, incluyendo efectos en la velocidad de circulación, tiempo de espera, confiabilidad de los tiempos de viaje, el bienestar de los pasajeros, el valor de los tiempos de espera y en vehículo, la elección de bus y ruta, y los niveles óptimos de frecuencia, tamaño vehicular y tarifa. La desutilidad del hacinamiento en trenes y buses es estimada en Sydney, Australia, con el objetivo de mostrar el impacto que tiene el hacinamiento en el valor estimado del tiempo en vehículo y en las estimaciones de demanda. Con un modelo logit multinomial, se muestra numérica y analíticamente que si la demanda de un servicio de transporte público se estima sin considerar al hacinamiento como fuente de desutilidad, la demanda será sobreestimada si el servicio se diseña para tener un número de pasajeros parados por sobre un umbral.
Transportation Research Part A: Policy and Practice, 2003
The measurement of service quality continues to be a challenging research theme and one of great ... more The measurement of service quality continues to be a challenging research theme and one of great practical importance to service providers and regulatory agencies. The key challenges begin with the identification of the set of potentially important dimensions of service quality perceived by passengers, current and potential. We then have to establish a way of measuring each attribute and identifying their relative importance in the overall calculation of satisfaction associated with existing service levels. Once a set of relevant attributes has been identified, this information can be integrated into programs such as monitoring and benchmarking, and even in contract specification. This paper, building on earlier research by the authors, investigates ways of quantifying service quality and comparing the levels within and between bus operators. The importance of establishing suitable market segments and the need to scale the service quality index for each operator to make meaningful comparisons is highlighted.
We illustrate and discuss several general issues associated with the random component of utility,... more We illustrate and discuss several general issues associated with the random component of utility, or more generally ''unobserved variability''. We posit a general conceptual framework that suggests a variance components view as an appropriate structure for unobserved variability. This framework suggests that ''unobserved heterogeneity'' is only one component of unobserved variability; hence, a more general view is required. We review a considerable amount of empirical research that suggests that random components are unlikely to be independent of systematic components, and random component variances are unlikely to be constant between or within individuals, time periods, locations, etc. We also review evidence that random components are functions of (elements of) systematic components. The latter suggests considerable caution in the use and interpretation of complex choice model specifications, in particular recently introduced forms of random parameter models that purport to estimate distributions of preference parameters. Several areas for future research are identified and discussed.
Transportation Research Part A: Policy and Practice, 2003
Populations of post-industrial nations are aging. With a growing number of people living well int... more Populations of post-industrial nations are aging. With a growing number of people living well into their 80's and maintaining active lives, the transportation system will have to start focussing more closely on understanding their mobility and accessibilty needs, so as to ensure that specific requirements of this large segment are not being ignored through the promotion of traditional 'solutions' and historical assumptions. This paper takes a close look at the evidence on the mobility needs and travel patterns of individuals over 64, distinguishing between the "young" elderly (aged 65 to 75 years) and the "old" elderly (over 75 years). This distinction is particularly useful in recognising the threshold of health change that impacts in a non-marginal way on mobility needs. This distinction also focuses transport planning and policy on a commitment to understanding the different needs of these subgroups of the population, identifying services and facilities that better cater for these groups. We review the evidence, in particular, on the mobility characteristics of the over 75 years age group, including how they secure support through migration and settlement patterns. We use the empirical evidence from a number of western nations to identify the role of conventional and specialised public transport as an alternative to the automobile in meeting mobility and accessibility needs.
A dominant theme in the debate on road pricing reform is securing buy in from all key stakeholder... more A dominant theme in the debate on road pricing reform is securing buy in from all key stakeholders as a precondition for gaining support from politicians. This paper explores the key influences and the extent to which particular road pricing schemes are acceptable to the community at large, and how this translates into support if a scheme were subject to a vote in a referendum. Using data collected in Sydney in 2012 from a sample of car users, we estimate a recursive simultaneous bivariate probit model that recognises the endogeneity effect of scheme acceptability on voting plans. We find that there is a very strong link between voting intentions and scheme acceptability, and provide a series of direct elasticity estimates of the influence that the cost elements of road pricing reform schemes have on the joint probability of accepting and voting for a scheme.
Transportation Research Part B: Methodological, 2009
This study presents a joint model system of residential location and activity time-use choices th... more This study presents a joint model system of residential location and activity time-use choices that considers a comprehensive set of activity-travel environment (ATE) variables, as well as sociodemographic variables, as determinants of individual weekday activity time-use choices. The model system takes the form of a joint mixed Multinomial Logit-Multiple Discrete-Continuous Extreme Value (MNL-MDCEV) structure that (a) accommodates differential sensitivity to the ATE attributes due to both observed and unobserved individual-related attributes, and (b) controls for the self selection of individuals into neighborhoods due to both observed and unobserved individual-related factors. The joint model system is estimated on a sample of 2793 households and individuals residing in Alameda County in the San Francisco Bay Area. The model results indicate the significant presence of residential self-selection effects due to both observed and unobserved individual-related factors. For instance, individuals from households with more bicycles are associated with a higher preference for out-of-home physically active pure recreational travel pursuits (such as bicycling around in the neighborhood). These same individuals locate into neighborhoods with good bicycling facilities. This leads to a non-causal association between individuals' time investment in out-of-home physically active pure recreational travel and bicycling facilities in their residential neighborhoods. Thus, ignoring the effect of bicycle ownership in the time-use model, would lead to an inflated estimate of the effect of bicycling facility density on the time invested in physically active pure recreational travel. Similarly, there are significant unobserved individual factors that lead to a high preference for physically active recreational activities and also make individuals locate in areas with good bicycling facilities. When such unobserved factors were controlled by the proposed joint residential location and time-use model, the impact of bicycling facility density on out-of-home physically active recreational activities ceased to be statistically significant (from being statistically significant in the independent time-use model). These results highlight the need to control for residential self-selection effects when estimating the effects of the activity-travel environment on activity time-use choices.
Conjoint Preference Elicitation Methods in the Broader Context of Random Utility Theory Preferenc... more Conjoint Preference Elicitation Methods in the Broader Context of Random Utility Theory Preference Elicitation Methods Hensher, Louviere & Swait 2 but some are not, some methods permit one to combine experimental with actual marketplace choice data but many do not, etc. Indeed, there are many ways to understand and model preferences and choices, some of which bear scant relation to one another and others that are incompatible, both theoretically and analytically. RUT offers a way to unify many seemingly disparate approaches to understand and model preference formation and choice. Figure represents an overview of the general problems covered by RUT, which can assist our understanding of the role of conjoint analysis methods within RUT. Figure should be regarded as a pedagogical vehicle to help explain why a more general view is required; it is not a theory per se.
Mixtures of revealed preference and stated preference data are recognised by transportation resea... more Mixtures of revealed preference and stated preference data are recognised by transportation researchers as offering a richness of behavioural input to travel choice modelling that is often absent from the isolated use of each data source. Accumulating evidence from various literatures, especially in marketing, psychology and transportation, provides support for the desirability of combining sources of preference data as a way of transferring increasing power of understanding of travel behaviour from the econometrics of a model to the underlying data inputs. Together with advances in the specification and estimation of discrete choice models, we are beginning to see that the simpler choice models such as multinomial logit (MNL) deliver an amazing amount of behavioural power providing that the underlying data specification is given a statistically rigorous treatment. There still remains however a growing role for more general choice models as a way of establishing the relevance of the simpler MNL model. This paper reviews the major contributions to the literature on combining sources of preference data and suggests new directions for fruitful research.
Transportation Research Part B-methodological, Apr 1, 2019
Discrete choice studies, with rare exception, assume that agents act as if sources of observed ut... more Discrete choice studies, with rare exception, assume that agents act as if sources of observed utility are captured through a linear in parameters and additive in attributes (LPAA) form, with some interactions. A growing number of transport (and other) choice studies have investigated one or more alternative processing rules adopted by agents in arriving at a choice, raising interest in how best to represent the utility expressions in a joint process and outcome choice model. Given the popular and appealing random parameter treatment of LPAA in mixed logit as a way of identifying non-systematic preference heterogeneity in a sample, this paper considers the possibility that we might be able to interact specific process heuristics with LPAA to uncover sources of systematic preference heterogeneity hidden in the standard LPAA form, and hence establish a link between the LPAA form and candidate process heuristics, offering a way to embellish and hence clarify the contributions to preference heterogeneity attributable to the presence of process heterogeneity. Specifically, we are interested in the extent to which there is a systematic relationship between the simple LPAA form and the more complex (albeit behaviourally realistic) process heuristics emerging in the transport literature which we call conditioning by random process heterogeneity (CRPH). In this paper, in addition to LPAA, we consider two process heuristics -Value Learning, and Relative Advantage Maximisation -with an overlay to account for risk attitudes, perceptual conditioning, and overt experience. The findings, using two data sets, suggest that empirically there exists a significant attribute-specific relationship between preference heterogeneity identified through specific process heuristics and through the LPAA assumption. How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins 1 How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins How to better represent preferences in choice models: the contributions to preference heterogeneity attributable to the presence of process heterogeneity Balbontin, Hensher and Collins
Transportation Research Part B-methodological, Jul 1, 2010
With the growing reliance on Stated Choice (SC) data, researchers are increasingly interested in ... more With the growing reliance on Stated Choice (SC) data, researchers are increasingly interested in understanding how respondents process the information presented to them in such surveys. Specifically, it has been argued that some respondents may simplify the choice tasks by consistently ignoring one or more of the attributes describing the alternatives, and direct questions put to respondents after the completion of SC surveys support this hypothesis. However, in the general context of issues with response quality in SC data, there are certainly grounds for questioning the reliability of stated attribute processing strategies. In this paper, we take a different approach by attempting to infer attribute processing strategies through the analysis of respondent-specific coefficient distributions obtained through conditioning on observed choices. Our results suggest that a share of respondents do indeed ignore a subset of explanatory variables. However, there is also some evidence that the inferred attribute processing strategies are not necessarily consistent with the stated attribute processing strategies. Additionally, there is some evidence that respondents who claim to have ignored a certain attribute may simply have assigned it lesser importance. The results produced by the inferring approach not only lead to slightly better fit but also more consistent results.
In recent years we have seen an explosion of research seeking to understand the role that rules a... more In recent years we have seen an explosion of research seeking to understand the role that rules and heuristics might play in improving the predictive capability of discrete choice models, as well as delivering willingness to pay estimates for specic attributes that may (and often do) dier signicantly from estimates based on a model specication that assumes all attributes are relevant. This paper adds to that literature in one important way-it explicitly recognises the endogeneity issues raised by typical attribute non-attendance treatments and conditions attribute parameters on underlying unobserved attribute importance ratings. We develop a hybrid model system involving attribute processing and outcome choice models in which latent variables are introduced as explanatory variables in both parts of the model, explaining the answers to attribute processing questions and explaining heterogeneity in marginal sensitivities in the choice model. The resulting empirical model explains how lower latent attribute importance leads to a higher probability of indicating that an attribute was ignored or that it was ranked as less important, as well as increasing the probability of a reduced value for the associated marginal utility coecient in the choice model. The model does so by treating the answers to information processing questions as dependent rather than explanatory variables, hence avoiding potential risk of endogeneity bias and measurement error.
Individual's process the information in stated choice (SC) experiments in many different ways. In... more Individual's process the information in stated choice (SC) experiments in many different ways. In order to accommodate decisions rules that are used in processing information, there is good sense in conditioning the parameterisation of stated choice design attributes on these rules. In particular, rules might be invoked to cope with the dimensionality of the SC design. In this paper we investigate the impact of rules such as attribute aggregation and reference dependency on preference profiles for specific design attributes, as well as the design specification, as we vary the dimensionality of an SC design. Prior to identifying the empirical differences in valuation of travel time savings due to design specification, we account for scale differences from pooling 16 stated choice designs. The heteroscedastic extreme value logit model is estimated to identify the role of design dimensionality and attribute processing rules, after accounting for scale differences across the pooled data designs The empirical evidence, drawn from a study in Sydney of car commuter route choice, suggests that accounting for the way that stated choice designs are processed, given their dimensionality, does make a statistically significant difference on measures of willingness to pay, as does accounting for scale differences between pooled data designs. This evidence has value in guiding the design of SC experiments and in adjusting results from different SC designs when comparing the evidence.
According to neoclassical economic theory, the only stated preference elicitation format that can... more According to neoclassical economic theory, the only stated preference elicitation format that can feasibly be employed in field studies to which truthful response can be the dominant strategy for all respondents is a single binary choice between the status quo and one alternative. In studies where the objective is estimation of preferences for multiple attributes of a good, it is preferred (and, in some cases, necessary) based on econometric considerations, to present respondents with a sequence of choice tasks. Economic theory predicts that utility-maximising respondents may find it optimal to misrepresent their preferences in this elicitation format. In this paper, the effect on stated preferences of expanding the number of choice tasks per respondent from one to four is tested using a split sample treatment in an attribute-based survey relating to the undergrounding of overhead electricity and telecommunications wires in the Australian Capital Territory. We find evidence to sugge...
A dominant theme in the debate on road pricing reform is securing buy in from all key stakeholder... more A dominant theme in the debate on road pricing reform is securing buy in from all key stakeholders as a pre-condition for gaining support from politicians. This paper explores the key influences and the extent to which particular road pricing schemes are acceptable to the community at large, and how this translates into support if a scheme were subject to a vote in a referendum. Using data collected in Sydney in 2012 from a sample of car users, we estimate a recursive simultaneous bivariate probit model that recognises the endogeneity effect of scheme acceptability on voting plans. We find that there is a very strong link between voting intentions and scheme acceptability, and provide a series of direct elasticity estimates of the influence that the cost elements of road pricing reform schemes have on the joint probability of accepting and voting for a scheme.
Research in Transportation Business & Management, 2021
This paper explores whether the benefits from major urban transport spending increases are likely... more This paper explores whether the benefits from major urban transport spending increases are likely to differ greatly, depending on whether that spending prioritises light rail, a mode with growing interest and several new services recently developed in Australia, major road network improvement or provision of additional bus services. It does this through a series of case studies based on Sydney, using MetroScan, an integrated transport and land use strategic model system. MetroScan is the most sophisticated strategic integrated land use, transport and economic system evaluation model in Australia, with the capability of exploring dynamic interactions between transport improvements, residential locations and job locations, among other things. We specifically focus on the impacts of major transport initiatives on reducing risks that people will be socially excluded because of poor mobility opportunities.
Transportation Research Part A: Policy and Practice, 2016
Uncertainty of travel times and the impact on travel choice behavior has been recognized as an in... more Uncertainty of travel times and the impact on travel choice behavior has been recognized as an increasingly important research direction in the past decade. This paper proposes an extension to the popular scheduling approach to modeling traveler's departure time choice behavior under uncertainty, with the main focus on a richer representation of uncertainty. This more general approach incorporates a separate term to reflect the risk aversion associated with uncertainty. Recognizing the correlation between expected schedule delay and travel time variability, the schedule delay components in the generalized approach are defined in terms of expected travel time, which differs from the scheduling approach. This approach is developed based on the analytical investigation of the relationship between the expected schedule delay and the mean and standard deviation of travel time. An analytical equivalence was found between the scheduling approach and the general approach given a departure time t. To investigate the empirical performance of the generalized approach, two state preference (SP) data sets are used; one from China with a symmetric travel time distribution and the other from Australia with an asymmetric distribution. Both studies show empirical evidence of an equivalence in respect of statistical fit between the generalized and the scheduling approaches, as found from analytical investigations. The Chinese study gives support in the generalized model to including both the mean-variance and the scheduling effects; whereas the Australian study finds only the mean-variance specification has statistical merit. Despite the different travel contexts, it is noteworthy in both empirical settings, that the parameter estimate for arriving earlier than the preferred arrival time (PAT) in the generalized model is positive. This suggests that commuters tend to prefer to arrive earlier in order to guarantee he/she will not be late. This paper contributes to a better understanding of performances of different reliability measures and their relationships. The practical value of the various unreliability measures is provided showing that these indicators are easy to obtain for inclusion in project appraisal.
Decisions made by businesses on where to locate or relocate are typically given less consideratio... more Decisions made by businesses on where to locate or relocate are typically given less consideration than residential location in integrated transport and land use modelling systems. This is surprising given the important role that businesses play in defining employment opportunities, and hence the travel patterns of workers and any travel associated with accessing firms. As part of a larger study on giving firm location choices an endogenous representation in an integrated model system, this paper reviews the existing literature on the drivers of location and relocation decisions in various geographical jurisdictions. The findings provide a starting position in the design of future firm-specific surveys and especially the attributes that are candidates for stated choice experiments and for inclusion in firm location utility equations embedded in integrated strategic model systems.
Hensher, D.A. Data challenges: more behavioural and (relatively) less statistical, invited plenar... more Hensher, D.A. Data challenges: more behavioural and (relatively) less statistical, invited plenary paper for Elsevier
Transportation Research Part A: Policy and Practice, 2017
The digital age has opened up new opportunities to improve the customer experience in using publi... more The digital age has opened up new opportunities to improve the customer experience in using public transport. Specifically, we see the role of smart technology in the hands of customers as the new rubric to deliver services that are individualised to the needs and preferences of current and future public transport users. This frontline of service delivery has become known as mobility as a service (MaaS) whereby an individual can book a service delivered through a range of possible modes of transport. Variations are bus-based options that include smart bookable 'point-via-point-to-point' services that offer options on travel times and fares as well as the continuation of conventional bus services where the market for smart MaaS is difficult or inappropriate to provide (e.g., contracted (often free) school bus services). This paper presents a number of positions that could potentially represent future contexts in which bus services might be offered, recognising that a hybrid multi-modal state of affairs may be the most appealing new contract setting, enabling the design of contracts to be driven by the mode-neutral customer experience, and the growing opportunity to focus on MaaS. We suggest that the adrenal rush for mobility services, however, may not deliver the full solution that supporters are suggesting.
El presente artículo examina las múltiples dimensiones que el hacinamiento de pasajeros tiene en ... more El presente artículo examina las múltiples dimensiones que el hacinamiento de pasajeros tiene en la demanda, la oferta y las operaciones de transporte público, incluyendo efectos en la velocidad de circulación, tiempo de espera, confiabilidad de los tiempos de viaje, el bienestar de los pasajeros, el valor de los tiempos de espera y en vehículo, la elección de bus y ruta, y los niveles óptimos de frecuencia, tamaño vehicular y tarifa. La desutilidad del hacinamiento en trenes y buses es estimada en Sydney, Australia, con el objetivo de mostrar el impacto que tiene el hacinamiento en el valor estimado del tiempo en vehículo y en las estimaciones de demanda. Con un modelo logit multinomial, se muestra numérica y analíticamente que si la demanda de un servicio de transporte público se estima sin considerar al hacinamiento como fuente de desutilidad, la demanda será sobreestimada si el servicio se diseña para tener un número de pasajeros parados por sobre un umbral.
Transportation Research Part A: Policy and Practice, 2003
The measurement of service quality continues to be a challenging research theme and one of great ... more The measurement of service quality continues to be a challenging research theme and one of great practical importance to service providers and regulatory agencies. The key challenges begin with the identification of the set of potentially important dimensions of service quality perceived by passengers, current and potential. We then have to establish a way of measuring each attribute and identifying their relative importance in the overall calculation of satisfaction associated with existing service levels. Once a set of relevant attributes has been identified, this information can be integrated into programs such as monitoring and benchmarking, and even in contract specification. This paper, building on earlier research by the authors, investigates ways of quantifying service quality and comparing the levels within and between bus operators. The importance of establishing suitable market segments and the need to scale the service quality index for each operator to make meaningful comparisons is highlighted.
We illustrate and discuss several general issues associated with the random component of utility,... more We illustrate and discuss several general issues associated with the random component of utility, or more generally ''unobserved variability''. We posit a general conceptual framework that suggests a variance components view as an appropriate structure for unobserved variability. This framework suggests that ''unobserved heterogeneity'' is only one component of unobserved variability; hence, a more general view is required. We review a considerable amount of empirical research that suggests that random components are unlikely to be independent of systematic components, and random component variances are unlikely to be constant between or within individuals, time periods, locations, etc. We also review evidence that random components are functions of (elements of) systematic components. The latter suggests considerable caution in the use and interpretation of complex choice model specifications, in particular recently introduced forms of random parameter models that purport to estimate distributions of preference parameters. Several areas for future research are identified and discussed.
Transportation Research Part A: Policy and Practice, 2003
Populations of post-industrial nations are aging. With a growing number of people living well int... more Populations of post-industrial nations are aging. With a growing number of people living well into their 80's and maintaining active lives, the transportation system will have to start focussing more closely on understanding their mobility and accessibilty needs, so as to ensure that specific requirements of this large segment are not being ignored through the promotion of traditional 'solutions' and historical assumptions. This paper takes a close look at the evidence on the mobility needs and travel patterns of individuals over 64, distinguishing between the "young" elderly (aged 65 to 75 years) and the "old" elderly (over 75 years). This distinction is particularly useful in recognising the threshold of health change that impacts in a non-marginal way on mobility needs. This distinction also focuses transport planning and policy on a commitment to understanding the different needs of these subgroups of the population, identifying services and facilities that better cater for these groups. We review the evidence, in particular, on the mobility characteristics of the over 75 years age group, including how they secure support through migration and settlement patterns. We use the empirical evidence from a number of western nations to identify the role of conventional and specialised public transport as an alternative to the automobile in meeting mobility and accessibility needs.
A dominant theme in the debate on road pricing reform is securing buy in from all key stakeholder... more A dominant theme in the debate on road pricing reform is securing buy in from all key stakeholders as a precondition for gaining support from politicians. This paper explores the key influences and the extent to which particular road pricing schemes are acceptable to the community at large, and how this translates into support if a scheme were subject to a vote in a referendum. Using data collected in Sydney in 2012 from a sample of car users, we estimate a recursive simultaneous bivariate probit model that recognises the endogeneity effect of scheme acceptability on voting plans. We find that there is a very strong link between voting intentions and scheme acceptability, and provide a series of direct elasticity estimates of the influence that the cost elements of road pricing reform schemes have on the joint probability of accepting and voting for a scheme.
Transportation Research Part B: Methodological, 2009
This study presents a joint model system of residential location and activity time-use choices th... more This study presents a joint model system of residential location and activity time-use choices that considers a comprehensive set of activity-travel environment (ATE) variables, as well as sociodemographic variables, as determinants of individual weekday activity time-use choices. The model system takes the form of a joint mixed Multinomial Logit-Multiple Discrete-Continuous Extreme Value (MNL-MDCEV) structure that (a) accommodates differential sensitivity to the ATE attributes due to both observed and unobserved individual-related attributes, and (b) controls for the self selection of individuals into neighborhoods due to both observed and unobserved individual-related factors. The joint model system is estimated on a sample of 2793 households and individuals residing in Alameda County in the San Francisco Bay Area. The model results indicate the significant presence of residential self-selection effects due to both observed and unobserved individual-related factors. For instance, individuals from households with more bicycles are associated with a higher preference for out-of-home physically active pure recreational travel pursuits (such as bicycling around in the neighborhood). These same individuals locate into neighborhoods with good bicycling facilities. This leads to a non-causal association between individuals' time investment in out-of-home physically active pure recreational travel and bicycling facilities in their residential neighborhoods. Thus, ignoring the effect of bicycle ownership in the time-use model, would lead to an inflated estimate of the effect of bicycling facility density on the time invested in physically active pure recreational travel. Similarly, there are significant unobserved individual factors that lead to a high preference for physically active recreational activities and also make individuals locate in areas with good bicycling facilities. When such unobserved factors were controlled by the proposed joint residential location and time-use model, the impact of bicycling facility density on out-of-home physically active recreational activities ceased to be statistically significant (from being statistically significant in the independent time-use model). These results highlight the need to control for residential self-selection effects when estimating the effects of the activity-travel environment on activity time-use choices.
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Papers by David Hensher