Stated Attribute Non‐attendance in Successive Choice Experiments

Attribute non‐attendance in choice experiments affects willingness‐to‐pay (WTP) estimates and therefore the validity of the method. A recent strand of literature uses attenuated estimates of marginal utilities of ignored attributes. Following this approach, we propose a generalisation of the mixed logit model, whereby the distribution of marginal utility coefficients of a stated non‐attender has a potentially lower mean and lower variance than those of a stated attender. Model comparison shows that our shrinkage approach fits the data better and produces more reliable WTP estimates. We further find that while reliability of stated attribute non‐attendance increases in successive choice experiments, it does not increase when respondents report having ignored the same attribute twice.     

Attribute Specific Impacts of Stated Non‐Attendance in Choice Experiments

In this paper, we generalise existing approaches to the treatment of stated attribute non‐attendance data in discrete choice experiments by allowing attribute specific impacts. We implement this approach by employing an extended hierarchical Bayes logit model specification. To illustrate this approach, we consider data collected to examine Indian consumers’ preferences for traditional aromatic rice varieties. Our results regarding stated attribute non‐attendance reveal that, our new approach shrinks marginal utilities of non‐attenders substantially compared to stated attenders, with significant differences in the shrinkage between some of the attributes. In addition, our results reveal the way in which non‐attendance of attributes interact with each other and the impact that this has on the distribution of willingness to pay estimates.     

Stated and Inferred Attribute Attendance Models: A Comparison with Environmental Choice Experiments

There is increasing evidence that respondents to choice experiment surveys do not consider all attributes presented in the choice sets. Not accounting for this ‘attribute non‐attendance’ leads to biased parameter estimates, and hence biased estimates of willingness to pay. Various methods exist to account for non‐attendance in the analysis of choice data, with limited agreement as to which method is ‘best’. This paper compares modelling approaches that can account for non‐attendance, based on stated and inferred attribute non‐attendance. Respondents' stated non‐attendance is incorporated in the specification of multinomial and mixed logit models. Inference of non‐attendance is based on equality constrained latent class models. Results show that model fit is significantly improved when attribute non‐attendance is taken into account, and that welfare estimates are lower when incorporating non‐attendance. The inference based on equality constrained latent class models provides the best model fit. There is little concordance between stated and inferred non‐attendance, suggesting that respondents may not answer attendance statements truthfully.     

Linking Consumers’ Food Choice Motives to their Preferences for Insect‐based Food Products: An Application of Integrated Choice and Latent Variable Model in an African Context

Consumers’ attitudes, perceptions, personalities and motives play important roles in shaping their food choices. These factors are not fully observed by analysts, so they should be treated as latent variables. A number of economic studies treat such variables as direct measures of consumers’ food choice behaviour, even though this might introduce measurement error and endogeneity bias. We investigate the latent link between consumers’ preferences and food choice motives (FCMs) in an African context. We use an integrated choice and latent variable (ICLV) model specification for data analysis to recognise the latent nature of the FCMs and address the measurement and bias problems. The data originate from an incentivised discrete choice experiment conducted in Kenya to elicit consumers’ preferences for insect‐based foods. Our findings show that consumers’ preferences and choices are influenced by their latent motivational orientation. The results illustrate the benefit of the ICLV approach in accounting for consumers’ latent preference constructs in food choice and valuation research.     

Design Factors Influencing Willingness‐to‐Pay Estimates in the Becker‐DeGroot‐Marschak (BDM) Mechanism and the Non‐hypothetical Choice Experiment: A Case of Biofortified Maize in Zambia

Two of the experimental methods used to estimate willingness‐to‐pay (WTP) for a non‐market good, the Becker‐DeGroot‐Marschak (BDM) mechanism and the non‐hypothetical choice experiment (nHCE) often lead to significantly different WTP estimates, complicating the choice between the methods. In Zambia the same group of researchers used both techniques to evaluate WTP for orange maize, which provides more vitamin A than other varieties. This provided an opportunity to analyse the sources of the difference. In the BDM experiment, one group of respondents was provided with more training opportunities than the other, and made higher bids. Accounting for lexicographic behaviour in the nHCE reduced the estimated WTP. These two design factors together resulted in a decrease in the WTP difference for orange maize (1,279–632 ZMK) although the difference remains statistically significant. More training was also shown to eliminate the effects of different orders in which maize varieties were presented.     

Combining Stated and Revealed Preferences on Typical Food Products: The Case of Dry‐Cured Ham in Spain

An extensive body of research concerns the valuation of EU certification schemes of quality based on the origin of food products. This literature focuses mainly on stated preferences (SPs) and reported behaviours by the consumers. We combine consumers’ SPs, obtained through a conjoint ranking experiment, with revealed preferences (RP), obtained through a retail scanner database. We evaluate SPs as predictors of RP, and investigate whether SPs and RPs are consistent. Dry‐cured ham in Spain is chosen as the anchor product, mainly because of its broad customer base and long history of origin certification. A ‘trick’ nested logit model with non‐identical and identical samples of consumers is estimated to answer each of the objectives. Results show that, irrespective of the analysed samples, SP can predict general market trends and choices but not accurately predict market shares, and that consumers’ actual behaviour is partly consistent with their SPs. We find that consumers prefer ham produced in Teruel, compared with unspecified Spanish origin. Quality Certification and a Distributor’s Brand are preferred over the alternatives of no quality label or identified with a brand owned by the producer. Interestingly, SPs for the Quality Certification and the distributor’s brand lead to an over‐ and under‐estimation, respectively, of the market share.     

Heterogeneous Demand and Supply for an Insurance‐linked Credit Product in Kenya: A Stated Choice Experiment Approach

We employ a discrete choice experiment to elicit demand and supply side preferences for insurance‐linked credit, a promising market‐based tool for managing agricultural weather risks and providing access to credit for farmers. We estimate preference heterogeneity using primary data from smallholder farmers and managers of lenders/insurers combined with household socio‐economic survey data in Kenya. We analyse the choice data using maximum simulated likelihood and Hierarchical Bayes estimation of a mixed logit model. Although there are some similarities, we find that there is conflicting demand and supply side preferences for credit terms, collateral requirements, and loan use flexibility. We also analyse willingness to buy and willingness to offer for farmers and suppliers, respectively, for the risk premium for different attributes and their levels. Identifying the preferred attributes and levels for both farmers and financial institutions can guide optimal packaging of insurance and credit providing market participation and adoption motivation for insurance‐bundled credit product.     

EU Food Safety Standards,Pesticide Use and Farm‐level Productivity: The Case of High‐value Crops in Kenya

This article provides an empirical analysis of the impact of European Union (EU) private food safety standards on pesticide use and farm‐level productivity among small‐scale vegetable producers in Kenya. We apply an extended three‐stage damage control production framework, accounting for multiple endogeneity problems, to farm‐level data collected from a random cross‐sectional sample of 539 small‐scale producers. Estimation results show that farmers producing vegetables for the domestic market use significantly lower quantities of pesticides than do export farmers. However, contrary to findings elsewhere, the econometric evidence here shows that both domestic and export‐oriented vegetable farmers in Kenya use pesticides at levels below the economic optimum. The results also show that the adoption of standards by export farmers does not have any significant impact on total pesticide use. However, adopter categories are distinguishable in terms of types of pesticide used, i.e. adopters use safer pesticides based on World Health Organization (WHO) classification. The third‐stage structural revenue model results demonstrate that adoption of standards has a positive and significant impact on revenue raised in vegetable production. Nevertheless, farmers producing for the export market are indistinguishable from those producing for the domestic farmers in terms of the total revenue earned from producing vegetables during the rainy season, on a ‘per acre’ basis. Although standards can potentially prevent resource‐poor smallholders from maintaining their position in the lucrative export markets, they can also result in positive changes in the production systems of those small‐scale farmers who adopt it, as shown by these results.     

The Lived Experience of Food Sovereignty: Gender,Indigenous Crops and Small‐Scale Farming in Mtubatuba,South Africa

Food sovereignty has become a powerful concept to critique the dominant global food regime. Although it has not taken root in South Africa as fiercely as elsewhere, we use this concept to explore how one small‐scale farmer seeks to wean herself from the dominant food system in the small town of Mtubatuba, KwaZulu‐Natal. Using ethnographic methods and in‐depth interviews about this single intense and extreme case, we explore this farmer's commitment and argue that it constitutes what we call the ‘lived experience of food sovereignty’. If food sovereignty is concerned with small‐farmer control over decisions about food cultivation, distribution and consumption, we examine this farmer's praxis and explore the obstacles she faces. These include gendered and racialized agrarian questions, land struggles, social reproduction and perceptions of her indigenous crops. We also examine the networks, knowledge, systems and methods that have allowed her to cultivate her self‐reliance.