摘要：数字化营销背景下，付费搜索广告作为电商商家获取流量的核心渠道，其点击率持续走低的问题严重制约营销效率。现有研究多聚焦广告信号，而忽视了产品信号及各类信号间的交互作用，难以完整刻画消费者的点击决策逻辑，因此厘清各类质量信号的作用机制及交互规律，具有重要的理论与实践意义。本文基于信号传递理论，以淘宝日用品类目下排名前60位商家85天的竞价广告数据为样本，构建固定效应模型，系统检验产品信号（产品相对价格、历史销量）与广告信号（产品与搜索相关性、广告排名）及其交互作用对付费搜索广告点击率的影响，并通过异质性、内生性及稳健性检验保障结论可靠性。研究发现，产品相对价格与点击率负相关，高相对价格会增加消费者的认知负荷、加剧其决策不确定性，进而抑制点击意愿；产品历史销量与点击率正相关，其高观察性特征能有效降低消费者的决策成本、强化信任感知。在信号交互作用方面，产品与搜索相关性会强化两类产品信号的作用：与产品相对价格形成信号叠加效应，进一步加大消费者认知负荷；与历史销量形成信号互补效应，有效验证销量的真实性。而广告排名仅弱化产品相对价格的负向影响，其与产品历史销量形成信号冗余，导致调节效应不显著。本文完善了基于信号来源的质量信号分类框架，揭示了产品信号的核心作用及广告信号的差异化调节逻辑，丰富了信号传递理论在付费搜索广告领域的应用。基于研究结论，电商商家应差异化运营产品信号、优化展示策略，根据产品信号属性匹配广告策略以发挥信号协同效应；同时理性看待广告排名价值、避免盲目竞价，从而实现营销资源高效配置，为优化付费搜索广告策略、提升广告效果提供实践参考。

Abstract: Paid search advertising, as a core channel connecting consumers with products, determines advertising value and marketing efficiency through its click-through rate (CTR), making it a critical concern for both academia and industry. Existing research mainly focuses on the impact of advertising signals on CTR, with insufficient attention to product signals and their interactions, making it difficult to fully explain the mechanisms and effects of different quality signals. Based on signal source (product or platform), this paper categorizes quality signals in paid search advertising into product signals (product relative price and historical sales) and advertising signals (query-product relevance and ad ranking). It further explores the impact of these two signal types and their interactions on CTR. Employing a hybrid approach that combines BERT model pre-labeling with double-blind manual verification to process data from the Taobao platform, this paper empirically examines the direct and interactive effects of these quality signals on CTR using a fixed-effects model. The findings reveal that product relative price negatively correlates with CTR, whereas product historical sales positively correlates with it. Furthermore, query-product relevance amplifies the effects of both product relative price and historical sales signals. Conversely, ad ranking attenuates the negative impact of product relative price on CTR. This research contributes by refining the classification framework for product quality signals, elucidating the primary pathways through which product signals influence CTR, and deciphering the interactive effects between advertising and product signals. The results offer practical insights for e-commerce merchants to optimally allocate resources, refine their signaling strategies, and enhance advertising performance.