提出新方法,用干预数据提升模型评估效率和准确性
Measuring Model Performance in the Presence of an Intervention
- 通过重加权处理组数据,模拟无干预时的分布
- 实验证明新方法在多种条件下更准确选出最优模型
- 适合需要高效利用干预数据的研究者使用
AI模型常基于预测结果的能力进行评估,但在社会影响类应用中,干预措施会改变结果,导致评估偏差。随机对照试验(RCT)虽可提供无偏评估,但仅使用对照组数据,浪费了处理组信息。本文理论分析了直接合并处理组与对照组性能估计带来的偏差,并推导出错误选型的条件。基于此,提出干扰参数加权(NPW)方法,对处理组数据重新加权,使其模拟无干预时的样本分布。在合成数据和真实数据上验证,该方法在不同干预效果和样本量下均优于传统忽略处理组数据的方法,显著提升了模型评估效率。该工作为实际场景中的高效模型评估提供了重要改进。
原文摘要 · Abstract (English)
AI models are often evaluated based on their ability to predict the outcome of interest. However, in many AI for social impact applications, the presence of an intervention that affects the outcome can bias the evaluation. Randomized controlled trials (RCTs) randomly assign interventions, allowing data from the control group to be used for unbiased model evaluation. However, this approach is inefficient because it ignores data from the treatment group. Given the complexity and cost often associated with RCTs, making the most use of the data is essential. Thus, we investigate model evaluation strategies that leverage all data from an RCT. First, we theoretically quantify the estimation bias that arises from naïvely aggregating performance estimates from treatment and control groups and derive the condition under which this bias leads to incorrect model selection. Leveraging these theoretical insights, we propose nuisance parameter weighting (NPW), an unbiased model evaluation approach that reweights data from the treatment group to mimic the distributions of samples that would or would not experience the outcome under no intervention. Using synthetic and real-world datasets, we demonstrate that our proposed evaluation approach consistently yields better model selection than the standard approach, which ignores data from the treatment group, across various intervention effect and sample size settings. Our contribution represents a meaningful step towards more efficient model evaluation in real-world contexts.
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