Modeling preference evolution in discrete choice models: A Bayesian state-space approach

We develop discrete choice models that account for parameter driven preference dynamics. Choice model parameters may change over time because of shifting market conditions or due to changes in attribute levels over time or because of consumer learning. In this paper we show how such preference evolution can be modeled using hierarchial Bayesian state space models of discrete choice. The main feature of our approach is that it allows for the simultaneous incorporation of multiple sources of preference and choice dynamics. We show how the state space approach can include state dependence, unobserved heterogeneity, and more importantly, temporal variability in preferences using a correlated sequence of population distributions. The proposed model is very general and nests commonly used choice models in the literature as special cases. We use Markov chain monte carlo methods for estimating model parameters and apply our methodology to a scanner data set containing household brand choices over an eight-year period. Our analysis indicates that preferences exhibit significant variation over the time-span of the data and that incorporating time-variation in parameters is crucial for appropriate inferences regarding the magnitude and evolution of choice elasticities. We also find that models that ignore time variation in parameters can yield misleading inferences about the impact of causal variables. This paper is based on the first author's doctoral dissertation.     

THE GENERAL STRUCTURE OF OPTIMAL INVESTMENT AND CONSUMPTION WITH SMALL TRANSACTION COSTS

We investigate the general structure of optimal investment and consumption with small proportional transaction costs. For a safe asset and a risky asset with general continuous dynamics, traded with random and time‐varying but small transaction costs, we derive simple formal asymptotics for the optimal policy and welfare. These reveal the roles of the investors' preferences as well as the market and cost dynamics, and also lead to a fully dynamic model for the implied trading volume. In frictionless models that can be solved in closed form, explicit formulas for the leading‐order corrections due to small transaction costs are obtained.     

Closing small open economy models

The small open economy model with incomplete asset markets features a steady-state that depends on initial conditions and equilibrium dynamics that possess a random walk component. A number of modifications to the standard model have been proposed to induce stationarity. This paper presents a quantitative comparison of these alternative approaches. Five different specifications are considered: (1) A model with an endogenous discount factor (Uzawa-type preferences); (2) a model with a debt-elastic interest-rate premium; (3) a model with convex portfolio adjustment costs; (4) a model with complete asset markets; and (5) a model without stationarity-inducing features. The main finding of the paper is that all models deliver virtually identical dynamics at business-cycle frequencies, as measured by unconditional second moments and impulse response functions. The only noticeable difference among the alternative specifications is that the complete-asset-market model induces smoother consumption dynamics.     

Net exports, consumption volatility and international business cycle models

Conventional two-country RBC models interpret countercyclical net exports as reflecting primarily the dynamics of capital. I show that, quantitatively, theoretical economies rely on counterfactual terms of trade effects: trade fluctuations, on the contrary, are driven by consumption smoothing, thus generating procyclical net trade in goods. I then consider a class of preferences that embeds home production in a reduced form: consumption volatility increases so that countercyclical net exports reflect primarily a strong relation between consumption and imports, as in the data. The major discrepancy between theory and data concerns the variability of international prices.     

A New Look at Constructed Choice Processes

Normative models of choice assert axiomatically that preferences are consistent, coherent, and determined only by relevant alternatives. In contrast to this classical economic perspective, behavioral models derived from research in psychology and consumer behavior assert that preferences are not guided by an internal, stable utility function but are constructed during the choice process. The current paper is based on a session on constructed choice processes (CCP) at the 2004 Choice Symposium that focused on how the standard CCP model can be enriched by bringing theories and tools from modern research in social cognition to bear on choice phenomenon. The richer conceptual framework presented by new, currently unpublished empirical work provides a novel perspective on choice construction by integrating the roles of subjective construal, experiential information, attribution, goals, and satisfaction in understanding preference construction processes in choice.     

Price-aware enhanced dynamic recommendation based on deep learning

Price is one of the essential elements influencing consumer purchase behavior. Like consumers’ preferences in products, their price preferences also dynamically change over time. However, dynamic price preferences haven’t been fully considered in existed recommendation studies. In this study, we propose a deep learning-based dynamic recommendation model by considering consumers’ dynamic preferences in both product and price. We specially design a review-and-rating-based sequence generator to select products whose prices the consumers are satisfied with to form the new purchase sequence. We also develop a multi-level attention mechanism in the transformer layer to explore the correlations between consumers’ price choices and to combine the price preferences with the product preferences. Experimental results show the proposed model outperforms the state-of-the-art models on some real-world datasets. Our findings can help retailers understand consumers’ price preferences and make informed decisions related to pricing, discounting, and bundle sales strategies.     

Integrating Time-Preferences into E-Negotiation Systems: A Model,Elicitation Approach and Experimental Implications

Researchers have advocated that the acquisition of user preferences is important to the successful adoption of electronic negotiation systems. In this paper, we focus on one such preference, namely time preference, wherein the price of a good/service varies according to the delivery/consumption time. Time preference is a behavioral aspect that varies across buyers. We discuss how different types of preferences can be elicited, represented and integrated with electronic negotiations. We discuss three experiments to study the effect of time preferences on negotiation. The first is a preference elicitation experiment involving 36 subjects. The next two are agent-to-agent negotiation experiments, one based on the individual preferences obtained earlier and the other based on an expanded dataset on both individual preferences as well as negotiation parameters. The agent-based experiment compares outcomes and efficiencies between the standard exponential discounting model and two behavioral models of time preference. Our results bring out the preferences of subjects, as well as the extent to which negotiation is affected and enhanced by the incorporation of time-preferences.     

AN EQUILIBRIUM GUIDE TO DESIGNING AFFINE PRICING MODELS

The paper examines equilibrium models based on Epstein–Zin preferences in a framework in which exogenous state variables follow affine jump diffusion processes. A main insight is that the equilibrium asset prices can be computed using a standard machinery of affine asset pricing theory by imposing parametric restrictions on market prices of risk, determined inside the model by preference and model parameters. An appealing characteristic of the general equilibrium setup is that the state variables have an intuitive and testable interpretation as driving the consumption and dividend dynamics. We present a detailed example where large shocks (jumps) in consumption volatility translate into negative jumps in equilibrium prices of the assets as agents demand a higher premium to compensate for higher risks. This endogenous “leverage effect,” which is purely an equilibrium outcome in the economy, leads to significant premiums for out‐of‐the‐money put options. Our model is thus able to produce an equilibrium “volatility smirk,” which realistically mimics that observed for index options.     

Closing large open economy models

A large class of international business cycle models admits multiple locally isolated deterministic steady states, if the elasticity of substitution between traded goods is sufficiently low. I explore the conditions under which such multiplicity occurs and characterize the dynamic properties in the neighborhood of each steady state. Models with standard incomplete markets, portfolio costs, a debt-elastic interest rate, or an overlapping generations framework allow for multiple steady states, if the model features multiple steady states under financial autarchy. If the excess demand for the foreign traded good is increasing in the good's own price in a given steady state, the equilibrium dynamics around this steady state are unbounded. Otherwise, the dynamics are bounded and unique. By contrast, with Uzawa-type preferences, the steady state is always unique and the associated equilibrium dynamics are always bounded and unique. The same results obtain under complete markets.     

Home bias and high turnover: Dynamic portfolio choice with incomplete markets

Why do investors trade a lot in foreign assets and hold so little of them in their portfolios? This paper shows that both observations can arise naturally in the presence of nondiversifiable nontraded consumption risk when each country specializes in production, preferences exhibit consumption home bias, and asset markets are incomplete. Using a general equilibrium two-country, two-sector (tradable and nontradable) model of the world economy with production I show that low diversification occurs because variations in relative prices (i) increase the riskiness of foreign assets and (ii) facilitate risk-sharing across countries. Large and volatile capital flows are necessary to take advantage of international risk premia differentials that occur in response to productivity changes in the nontradable sector. I characterize the optimal portfolio holdings, the evolution of the investment opportunity set, the risk premium, and the dynamics of capital flows using a new methodology for solving dynamic general equilibrium models with incomplete markets and portfolio choice.     

ERROR-CORRECTION, ⇐ SURPRISE ⇒ MODELS AND THE DIFFERENTIAL APPROACH TO THE CONSUMPTION FUNCTION(*)

The paper provides a general theoretical framework that allows a comparison and a possible reconciliation of error correction models of consumers’behaviour and the life cycle hypothesis under rational expectations. It is suggested that by relaxing the assumption of intertemporally strongly separable and homothetic preferences, a generalization of Hall's random walk model can be derived, containing an error correction mechanism.     

Preference adjustment and opportunities for agreement: Decision modeling to assess negotiating flexibility at UNCED

This paper develops a conceptual framework and applies it to analyze the dynamics of national interests in prenegotiation. The study's goals are to develop a systematic approach for analyzing prenegotiation processes and provide results that will have practical utility for negotiators. Specifically, the approach is applied to the prenegotiation process of the 1992 United Nations Conference on Environment and Development (UNCED), examining the financial resources issue, in particular. Decision analytic models were built to account for three key negotiation actors, and sensitivity analyses were performed to evaluate the incremental modifications to issue preferences required to achieve mutually acceptable compromises. Conclusions are drawn that indicate the extent of flexibility required of key negotiation actors to take advantage of the opportunities for agreement in the financial resources issue area. The conceptual framework and methodological approach explored in this paper can provide practical assistance as a planning tool for negotiators, helping them to diagnose the situation and plan strategies for future environmental and other multilateral negotiations. The approach can suggest specific opportunities for compromise and the degree and type of flexibility needed to achieve a convergence of interests on the issue.     

Comprehensive Trade Agreements: Conditioning Globalisation or Eroding the European Model?

Trade dynamics within the EU are presently pushing it towards deepening globalisation through bilateral comprehensive trade agreements which establish far-reaching rules that govern the bilateral trade relationship. The European Commission has defended these agreements as a vehicle through which to promote world trade in accordance with European values and norms. However, the theory of fiscal federalism and the principle of subsidiarity tell us that one should not centralise decisions at the supranational level which are better taken at the national or regional level when there are different preferences among countries or regions. Consequently, member state and regional competences ought not to be perceived as a mere obstacle to swift trade deals. Rather, they can provide an important checks and balances function with regard to whether EU trade policy is truly working to condition globalisation according to European values and preferences.     

Conjoint models of family decision making

The objective of this research is to develop viable approaches to modeling joint decisions. Using conjoint-analysis-type preference data, three methods are developed to combine individual preferences to approximate joint preferences and predict joint decisions. The first is an equal weighting model, which is a simple average of individual members' part-worth utilities. The second is a relative influence model, which combines individual utility functions using a measure of derived influence. The third is a conflict resolution model, which combines utility functions using a measure of conflict. In addition to these three combination models, individual member models and a joint model based on the joint preferences are available.The application area in which the models are operationalized is family decision making. The decision involves choice of a job by MBA students and spouses at a major private university. The models are first calibrated using preference data on hypothetical jobs from MBAs, spouses, and couples and then evaluated on their ability to predict the actual job chosen.     

Optimal retail sales strategies for old and new products in monopoly and horizontal competition scenarios

Advances in technology have made product updates more frequent and allowed consumers to choose different versions of the same product based on their preferences. It is crucial for retailers to understand how to formulate optimal sales strategies based on those different consumer preferences. To this end, we develop game models that consider the heterogeneity of consumer preferences under both monopoly and horizontal competition scenarios and perform the sensitivity analysis to examine the impact of consumer proportions and consumer preferences on retailers’ sales strategies. The results show that (i) regardless of competition or monopoly status, the original retailer can always maximize profit by setting prices based on the market share of traditional consumers, as long as the retailer sells both new and old versions of the product; (ii) the greater the competitive advantage of the competitor, the more advantageous the hybrid sales mode; (iii) if the price of the old product is below a certain threshold, there will be a positive profit for the original retailer when selling both the old and new products; and (iv) when consumer acceptance of competing retailers is lower, entering the retail market is not a good choice for competing retailers.     

Children's perception of food and healthy eating: dynamics behind their food preferences

Childhood obesity epidemic has been a popular topic for research as it has become a major health concern in many countries. As the focus of earlier studies has been predominantly on food marketing to children, there is still limited research on what other factors, apart from food marketing, influence their food preferences and eating habits. Bringing in children's perspectives as well as those of parents and guardians, this study aims to fill this gap by shedding light on further dynamics that can be influential on children's preferences. Through a qualitative inquiry, focus groups and individual interviews were conducted with children between the ages of 7 and 11. Aiming to investigate both meanings and practices, these sessions also included interactive and participatory research methods such as drawing, word games and role playing. Moreover, in-depth interviews were carried out with teachers and mothers to gain an understanding of their perspective on the topic. The findings show the different appeals and social influences behind children's food preferences, among which sensory and fun appeals as well as the influence of parents come forward. By revealing these different appeals of food and social influences, the study brings a new perspective to the discussions on childhood obesity and food marketing.     

Escaping a protectionist rut: Policy mechanisms for trade reform in a democracy

This paper analyzes the dynamics of trade policy reform under democracy. In an overlapping generations model, heterogeneous agents may acquire skills when young thereby determining the skill composition of their cohort. Current and anticipated trade policies influence education decisions and thus voters' trade policy preferences. We show that there may exist two political steady states: one protectionist and one liberal. Transition from the former to the latter can be achieved by government announcements, temporary educational subsidies, or tariff liberalization by trading partners, but generally not by transfer payments to adversely affected workers. We find additionally that reform is politically feasible only if the proposed liberalization is sufficiently large, suggesting that radical reform may be necessary for escaping a protectionist political rut.     

Enhancing Consumer Choice: Are We Making Appropriate Recommendations?

To reduce information search costs, consumers often use choice-making aids. If these aids are to help consumers make choices consistent with their own preferences, as well as reduce search effort, they must be based on choke models consistent with consumers' true preference sets. This study used conjoint analysis to identify these ideal choice models. Thirty-six percent of the subjects were found to use compensatory choice models and 64 percent noncompensatory models. The results suggest a need to base choice-making aids on ideal choice models if the aid is to lead consumers to decisions consistent with true preferences.     

Strategic Behavior in Contested-Pile Methods for Fair Division of Indivisible Items

Most fair-division procedures are modeled on cake-cutting procedures such as “I cut, you choose”. The inputs are players’ choices, which are assumed to reflect preferences but not fully reveal them; the output is a division that is in some sense fair. However, it seems likely that decision makers sometimes behave insincerely, that is, they make choices that are not consistent with their true preferences. For example, strategic—as opposed to sincere—behavior may be aimed at taking advantage of information about an opponent’s preferences, which most fair-division procedures assume is not available. We focus on contested-pile procedures, a class of procedures for the fair division of indivisible items between two players, related to the alternation procedures proposed by Brams and Taylor (The win-win solution: guaranteeing fair shares to everybody. W. W. Norton, New York, 1999). We use computational models to assess the performance of these procedures under both sincere and strategic behavior. We show how available information about preferences can interact with strategy to shape outcomes. Our results indicate that strategic behavior, although it often changes outcomes, may not make them less efficient or less fair. Furthermore, our investigation suggests that how information about the opponents preference is processed does not have a strong impact, in that a conceptually simple strategy often outperforms a more elaborate one.