Does Online Fundraising Increase Charitable Giving? A Nationwide Field Experiment on Facebook
中文摘要
线上筹款能否增加慈善捐赠?我们利用 Facebook 广告工具,在德国全国范围内实施了一项自然田野实验,将近 8,000 个邮政编码随机分配至“救助儿童会”(Save the Children)筹款视频组或纯控制组。我们按邮政编码研究了“救助儿童会”及其他慈善机构捐赠收入与捐赠频率的变化。我们的地理随机化设计规避了基于点击数据的研究所固有的诸多困难,尤其是替代与测量问题。我们发现:(i) 视频筹款在活动期间及其后的五周内提高了“救助儿童会”获得的捐赠收入和捐赠频率;(ii) 该活动对筹款方而言是有利可图的;(iii) 效应在不同视频内容和曝光分配策略下表现相似。然而,我们也发现对其他类似慈善机构或项目的捐赠存在一定程度的挤出。最后,我们展示点击数据可能不是捐赠的合意代理指标,并建议管理者采用审慎的实验设计,以便能够合理评估广告对相关结果的影响。
Abstract
Does online fundraising increase charitable giving? Using the Facebook advertising tool, we implemented a natural field experiment across Germany, randomly assigning almost 8,000 postal codes to Save the Children fundraising videos or to a pure control. We studied changes in the donation revenue and frequency for Save the Children and other charities by postal code. Our geo-randomized design circumvented many difficulties inherent in studies based on click-through data, especially substitution and measurement issues. We found that (i) video fundraising increased donation revenue and frequency to Save the Children during the campaign and in the subsequent five weeks, that (ii) the campaign was profitable for the fundraiser, and that (iii) the effects were similar independent of video content and impression assignment strategy. However, we also found some crowding out of donations to other similar charities or projects. Finally, we demonstrated that click data may be an inappropriate proxy for donations and recommend that managers use careful experimental designs that can plausibly evaluate the effects of advertising on relevant outcomes.