Information seeking conversations between users and Conversational Search Agents (CSAs) consist of multiple turns of interaction. While users initiate a search session, ideally a CSA should sometimes take the lead in the conversation by obtaining feedback from the user by offering query suggestions or asking for query clarifications i.e. mixed initiative. This creates the potential for more engaging conversational searches, but substantially increases the complexity of modelling and evaluating such scenarios due to the large interaction space coupled with the trade-offs between the costs and benefits of the different interactions. In this paper, we present a model for conversational search -- from which we instantiate different observed conversational search strategies, where the agent elicits: (i) Feedback-First, or (ii) Feedback-After. Using 49 TREC WebTrack Topics, we performed an analysis comparing how well these different strategies combine with different mixed initiative approaches: (i) Query Suggestions vs. (ii) Query Clarifications. Our analysis reveals that there is no superior or dominant combination, instead it shows that query clarifications are better when asked first, while query suggestions are better when asked after presenting results. We also show that the best strategy and approach depends on the trade-offs between the relative costs between querying and giving feedback, the performance of the initial query, the number of assessments per query, and the total amount of gain required. While this work highlights the complexities and challenges involved in analyzing CSAs, it provides the foundations for evaluating conversational strategies and conversational search agents in batch/offline settings.

中文翻译：

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在会话搜索期间分析混合计划和搜索策略

用户和会话搜索代理 (CSA) 之间的信息搜索会话由多轮交互组成。当用户发起搜索会话时，理想情况下，CSA 有时应该通过提供查询建议或要求查询澄清（即混合主动性）来获取用户的反馈，从而在对话中发挥主导作用。这为更具吸引力的对话搜索创造了潜力，但由于大的交互空间以及不同交互的成本和收益之间的权衡，大大增加了建模和评估此类场景的复杂性。在本文中，我们提出了一个对话搜索模型——从中我们实例化了不同的观察到的对话搜索策略，其中代理引出：（i）先反馈，或（ii）后反馈。我们使用 49 个 TREC WebTrack 主题进行了分析，比较了这些不同策略与不同混合倡议方法的结合程度：(i) 查询建议与 (ii) 查询澄清。我们的分析表明，没有优势或优势组合，相反，它表明当首先询问时查询澄清更好，而在呈现结果后询问查询建议时更好。我们还表明，最佳策略和方法取决于查询和提供反馈之间的相对成本、初始查询的性能、每个查询的评估次数以及所需的总收益之间的权衡。虽然这项工作强调了分析 CSA 所涉及的复杂性和挑战，