The proneness of stated preference methods to different biases has increased the popularity of incentivized choice experiments (ICE). ICEs, however, are not free from challenges. One such challenge when using ICEs in market valuation is that some product alternatives may not be available to incentivize experiments. In this context, withholding information about product availability could be considered deception while disclosing information raises questions regarding influences on participants’ choice behavior. The present study explores this issue by changing the number of available product alternatives in an induced value choice experiment. Participant engagement is captured using an eye-tracking and measurement scales. The results suggest, while incentives matter, engagement matters more. A random-effects logit estimation reveals that engagement is positively correlated with profit-maximizing behavior, while the number of available alternatives is not. A similar result of engagement holds after accounting for differences in payouts between alternatives. In contrast, the same thing cannot be said for number of available alternatives. When the difference between potential payouts is small, no number of available alternatives has a significant effect on profit-maximizing behavior. When the difference between payouts is larger, any number of available alternatives increases the likelihood of choosing the profit-maximizing choice. The findings suggest that researchers could successfully conduct ICE with trustworthy results without having all the product alternatives being available as long as participants are engaged in the choice task.

陈述的偏好方法倾向于不同的偏见增加了激励选择实验（ICE）的普及。但是，ICE并非没有挑战。在市场评估中使用ICE时，这样的挑战之一是某些产品替代品可能无法用于激励实验。在这种情况下，扣留有关产品可用性的信息可能被视为欺骗，而披露信息则引发了有关对参与者选择行为的影响的问题。本研究通过在诱导价值选择实验中更改可用产品替代品的数量来探索这一问题。参与者的参与度使用眼动和测量标尺进行捕捉。结果表明，尽管激励措施很重要，但参与更重要。随机效应logit估计显示参与度与利润最大化行为呈正相关，而可用替代方案的数量则不然。在考虑了替代方案之间的支出差异之后，参与度的结果相似。相反，对于可用替代方案的数量，不能说相同的话。当潜在支出之间的差异很小时，没有任何可用的替代方法会对利润最大化行为产生重大影响。当支出之间的差异较大时，任何数量的可用替代方案都会增加选择获利最大化选择的可能性。研究结果表明，只要参与者参与选择任务，研究人员就可以成功进行ICE，获得可信赖的结果，而无需使用所有替代产品。