本研究旨在探討賣方分析師受到經濟政策不確定性升高時的行為傾向。分析師有誘因提高市場參與者對其預測能力（和名譽）的評價；基於自我歸因偏差的論點，本研究預期經濟不確定性與分析師的羊群行為呈負向關係。本文透過Baker et al. (2016)建構的經濟政策不確定性指數（Economic Policy Uncertainty Index, EPU ）及I/B/E/S證券分析師資料庫在1989年至2022年間的資料進行分析，透過實證顯示其之間確屬存在負向關聯。並且本研究亦發現當分析師面對受預測公司盈餘品質較佳、營運波動較低時，EPU促使其發佈非羊群建議的效果更為明顯。此結果與Trueman (1994)及Graham (1999)預測先前資訊的不確定性程度將影響分析師模仿其他分析師預測相同，亦符合Song (2009)的結果，並彌補了分析師受到經濟政策不確定性時的相關研究。

This study aims to explore the behavioral tendencies of sell-side analysts in response to heightened economic policy uncertainty. Analysts have incentives to enhance market participants' evaluations of their forecasting ability (and reputation). Based on the argument of self-attribution bias, this study expects a negative relationship between economic uncertainty and analysts' herding behavior. Using the Economic Policy Uncertainty Index (EPU) constructed by Baker et al. (2016) and data from the I/B/E/S securities analyst database from 1989 to 2022, the empirical analysis reveals a negative correlation between economic policy uncertainty and analysts' herding behavior. Furthermore, the study finds that when analysts assess companies with higher earnings quality and lower operational volatility, the effect of EPU in promoting non-herding recommendations is more pronounced. This result aligns with the predictions of Trueman (1994) and Graham (1999) that the uncertainty of prior information influences analysts' tendency to mimic other analysts' forecasts. It also corroborates the findings of Song (2009) and supplements the existing research on the impact of economic policy uncertainty on analysts.

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