Food discrete choice experiments typically define product alternatives with a researcher-predetermined and sometimes arbitrary quantity. Results reveal that the use of a researcher-prespecified experimental quantity leads to biased welfare estimates. Differences in marginal utility of money are found with a resulting upward bias in willingness to pay estimates when small pre-defined product quantities are used. Higher-income consumers show more evident bias. This evidence cautions the use of a researcher-predetermined quantity to design alternatives in choice tasks and also proposes an alternative experimental design that accounts for these effects by matching the quantity in experiments to consumer’s actual purchase quantity.

中文翻译：

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实验数量、心理预算和食物选择：离散选择实验应用

食品离散选择实验通常用研究人员预先确定的、有时是任意数量的产品替代品来定义。结果表明，使用研究人员预先指定的实验数量会导致福利估计有偏差。当使用少量预定义产品时，货币边际效用的差异会导致支付意愿的向上偏差。高收入消费者表现出更明显的偏见。该证据提醒使用研究人员预先确定的数量来设计选择任务中的替代品，并且还提出了一种替代实验设计，通过将实验中的数量与消费者的实际购买数量相匹配来解释这些影响。