Assumption-Lean Shrinkage and Model Averaging for Spatial Parameters
空间参数的假设稀疏收缩与模型平均
Harvey Barnhard
AI总结 针对空间相关单元的参数估计噪声问题,提出基于SURE的收缩估计器选择与平均方法,在应用中将均方误差降低约27%。
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经济决策通常依赖于许多关于邻里效应、学校质量和医院绩效的噪声估计。收缩估计可以通过跨相关单元汇集信息来减少这种噪声。当单元通过地理、邻接或共享特征相关联时,主要挑战不仅在于收缩多少,还在于哪些关系应指导汇集。我们使用Stein无偏风险估计(SURE)来选择和平均灵活的收缩估计器,允许研究人员比较相关性的候选定义,而不将任何先验、协方差模型或邻接规则视为潜在参数的真实模型。在直接对估计量映射施加的正则条件下,SURE选择的表现几乎与候选类中的最佳规则一样好。SURE选择的加权平均同样几乎与训练候选者的最佳固定加权平均一样好,包括其拟合值使用完整噪声估计向量的非线性收缩规则。在应用于20个通勤区的机会图谱经济流动性数据时,最佳个体空间规范因区域而异,而SURE选择的平均将报告的SURE估计均方误差相对于表现最佳的非空间经验贝叶斯基准降低了约27%。
Economic decisions often depend on many noisy estimates of neighborhood effects, school quality, and hospital performance. Shrinkage estimation can reduce this noise by pooling information across related units. When units are related through geography, adjacency, or shared characteristics, the main challenge is not only how much to shrink, but which relationships should guide pooling. We use Stein's Unbiased Risk Estimate (SURE) to select among and average over flexible shrinkage estimators, allowing researchers to compare candidate definitions of relatedness without treating any one prior, covariance model, or adjacency rule as the true model for the latent parameters. Under regularity conditions stated directly on the estimator maps, SURE selection performs nearly as well as the best rule in a candidate class. The SURE-chosen weighted average likewise performs nearly as well as the best fixed weighted average of trained candidates, including nonlinear shrinkage rules whose fitted values use the full vector of noisy estimates. In an application to Opportunity Atlas economic mobility data from 20 commuting zones, the best individual spatial specification varies across zones, and the SURE-chosen average reduces reported SURE-estimated mean squared error by about 27% relative to the best-performing non-spatial empirical Bayes benchmark.