hedging effect

隨著資訊時代的來臨，電腦資訊檢索系統之重要性與日俱增，而良好系統之設計與評估實有賴對讀者相關判斷行為之研究。在影響相關判斷的眾多因素中，文獻展現次序這項變數是系統所易於控制的，且許多研究發現，訊息呈現次序的不同可能導致受試者判斷結果產生改變，因此對文獻展現次序進行深入探討實有其必要性。有鑑於此，本文首先對文獻展現次序所造成之「次序效應」進行文獻分析，並以本土化之實證研究驗證次序效應中之「賭注效應」，同時以多種筆數之文獻組設計觀察文獻筆數對次序效應產生之影響，以期對資訊檢索系統之設計有些許助益。

Among the numerous variables which influence relevance judgment, document presentation order has been attested to be actually influential by many studies. Since this variable is easy to be controlled by automated information retrieval system, it deserves our more attention and discussion. There are three points in this article: (1) to review the literature on "order effects", which is induced by document presentation order; (2) to verify the hypothesis of "hedging effect", which is one kind of order effect, by a two-stage experiment; and (3) to identify the relationship between number of document and hedging effect.