发表机构
Columbia University（哥伦比亚大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究提出随机时长切换实验的频域设计准则，通过优化双速率族得到随运行年龄变化的切换规则，将最坏情况均方误差降低至少32%。
AI 中文摘要
切换实验（switchback experiment）在时间上交替地让整个系统处于处理组或对照组。当单元之间的交互作用可能削弱标准的单元级实验时，这种方法尤其有用。切换实验通常在固定的时间网格上实施，这给处理切换的时间施加了高度结构化的限制。我们研究了一类更广泛的随机时长切换实验，其中处理组和对照组在多个运行期间交替，这些运行的时长从共同分布中抽取。在有限结转效应下，我们证明了霍维茨-汤普森估计量的均方误差具有简单的频域表示，该表示由时间结果模式与设计引起的失衡和污染模式的对齐方式决定。这一表示产生了一个易于处理的、最坏情况下的设计准则，该准则可以直接从时长分布计算得出。即使在简单的双速率族上进行优化，也能产生一个随运行年龄变化的切换规则，与标准的独立随机化固定块切换实验相比，该规则将渐近最坏情况下的均方误差至少降低了32%。
英文摘要
A switchback experiment alternates an entire system between treatment and control over time. It is especially useful when interactions between units can undermine standard unit-level experiments. Switchback experiments are commonly implemented on fixed temporal grids, which impose highly structured restrictions on when treatment can switch. We study a broader class of random-duration switchbacks, in which treatment and control alternate across runs whose durations are drawn from a common distribution. Under finite carryover, we show that the mean squared error of the Horvitz-Thompson estimator has a simple frequency-domain representation governed by how temporal outcome patterns align with design-induced imbalance and contamination patterns. This representation yields a tractable worst-case design criterion that can be computed directly from the duration distribution. Optimizing over even a simple two-rate family produces a run-age-dependent switching rule that reduces the asymptotic worst-case mean squared error by at least 32\% relative to the standard independently randomized fixed-block switchback.
