Northstone Kate, Bowring Claire
Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom.
PLoS One. 2025 Jan 28;20(1):e0316534. doi: 10.1371/journal.pone.0316534. eCollection 2025.
Financial incentives may be important for improving response rates to data collection activities and for retaining participants in longitudinal studies. However, for large studies, this introduces significant additional costs. We sought to determine whether an opt-in or an opt-out option for receiving financial incentives when completing questionnaires offers any cost saving measures.
The Avon Longitudinal Study of Parents and Children has been ongoing for more than 30 years. It has offered a £10 incentive for returning a partly or fully completed annual questionnaire for >10 years, this is provided by default unless a participant chooses to opt out. For questionnaires completed in 2020 by the original parents recruited to the study and by their offspring, we randomised eligible participants to either opt-out or to opt-in to receiving their vouchers. Logistic regressions determined whether opt-out or opt-in made any difference to the proportion of respondents receiving their vouchers.
Respondents are less likely to choose to receive a thank you for their time in the form of a £10 shopping voucher if they are asked to opt in compared to if they are asked to opt out. The odds ratio, adjusted for baseline characteristics was 3.94 (95% Confidence Interval: 3.49, 4.45). There was no difference in response rates according to whether respondents were randomised to the opt-in or opt-out group.
ALSPAC now employs an opt-in procedure for respondents receiving their financial incentive when completing a questionnaire. We recommend similar studies that rely on volunteers consider this option if they want to introduce some cost savings without harming overall response rates.
经济激励对于提高数据收集活动的回应率以及使参与者继续参与纵向研究可能很重要。然而，对于大型研究而言，这会带来显著的额外成本。我们试图确定在完成问卷时选择加入或选择退出接受经济激励的方式是否能提供任何节省成本的措施。
雅芳亲子纵向研究已经进行了30多年。在超过10年的时间里，对于返还部分或全部完成的年度问卷提供10英镑的激励，默认提供此激励，除非参与者选择退出。对于2020年由最初招募到该研究的父母及其后代完成的问卷，我们将符合条件的参与者随机分为选择退出或选择加入以领取代金券。逻辑回归确定选择退出或选择加入是否对领取代金券的受访者比例有任何影响。
与被要求选择退出相比，如果被要求选择加入，受访者不太可能选择接受以10英镑购物代金券形式表示的感谢。根据基线特征调整后的优势比为3.94（95%置信区间：3.49，4.45）。根据受访者被随机分配到选择加入组还是选择退出组，回应率没有差异。
雅芳亲子纵向研究现在采用选择加入程序，让受访者在完成问卷时接受经济激励。我们建议依赖志愿者的类似研究，如果想在不损害总体回应率的情况下节省一些成本，可以考虑这个选项。
