When Is Neyman-Orthogonal Inference Feasible? Existence and Relevance
何时能够进行奈曼正交推断?存在性与信息相关性
Neyman-orthogonal moments underpin debiased and double machine learning, yet their existence and informativeness are typically presumed. We ask three questions: when do nontrivial orthogonal moments exist, which target directions contain first-order information, and does a proposed moment detect all such directions? Restricted local overidentification characterizes existence under attainability. Effective Fisher information determines relevance; its rank counts informative…