SITE SELECTION BIAS IN PROGRAM EVALUATION
SITE SELECTION BIAS IN PROGRAM EVALUATION
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DOI：
10.1093/qje/qjv015
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发表时间：
2015-08-01
影响因子：
13.7
通讯作者：
Allcott, Hunt
中科院分区：
文献类型：
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作者：
Allcott, Hunt
当一个项目被采用或评估的概率与其影响相关时，就可能出现“选址偏差”。在Opower节能项目的背景下，我测试选址偏差，使用111个随机对照试验，涉及860万户美国家庭。基于前10次重复的丰富微观数据的预测大大夸大了接下来101个地点的疗效。几种机制导致了这种积极的选择。例如，在更环保的地区，公用事业更有可能采用该计划，他们的客户对处理的反应更积极。此外，由于公用事业公司最初的目标是治疗高使用量的消费者亚群，疗效下降，因为该计划后来扩大。结果表明，即使经过多次重复，程序评估仍然可以系统地给出有偏见的样本外预测。
"Site selection bias'' can occur when the probability that a program is adopted or evaluated is correlated with its impacts. I test for site selection bias in the context of the Opower energy conservation programs, using 111 randomized control trials involving 8.6 million households across the United States. Predictions based on rich microdata from the first 10 replications substantially overstate efficacy in the next 101 sites. Several mechanisms caused this positive selection. For example, utilities in more environmentalist areas are more likely to adopt the program, and their customers are more responsive to the treatment. Also, because utilities initially target treatment at higher-usage consumer subpopulations, efficacy drops as the program is later expanded. The results illustrate how program evaluations can still give systematically biased out-of-sample predictions, even after many replications.