本研究將搜集到的原始數據整理為追蹤資料（panel data），以固定效應模型驗證中國大陸P2P網路借貸羊群效應的存在性，并探討其產生的機制，發現羊群效應隨著借款進度的增加而不斷減弱，且相較資訊多的借款標的，資訊較少的借款標的初期羊群效應更加明顯，羊群效應減弱的速度更快。進一步，本文利用傾向得分匹配（PSM）方法，檢驗羊群效應與可能發生的違約率的關係，結果表明，羊群效應對於預測借款標的未來是否會違約有著積極的作用。將樣本按照資訊量的大小進行分組再次進行匹配後發現，借款標的的資訊量對於“羊群效應”能否傳遞資訊、預測違約情況有著較大的影響，當資訊量較多時，投資者會變得盲目自信，更傾向於相信自己的判斷，此時的羊群效應多為“偽羊群效應”；而當資訊量少時，投資者們變得謹慎，傾向於參考之前投資者的行為進行決策，理性的羊群效應此時就傳遞了有用的資訊。

This study sorts the collected raw data into panel data, uses the fixed-effects model to verify the existence of herd effect in the P2P lending in mainland China, and explores its mechanism. We find that although the herd effect exists, it is not static. As the amount of the investment increases, it becomes weak and gradually disappear. Compared with the loans with more hard information, the herd effect of that with less hard information is more obvious in the initial stage, and the herd effect weakens faster. Furthermore, this paper uses the propensity score matching (PSM) method to test the relationship between the herd effect and the possible default. The results show that herd effect plays a positive role in predicting the future default of the loans. After classifying the samples according to the amount of information and matching them again, we find that the amount of information of the loans has a great influence on whether the herd effect can transmit information and predict the likelihood of defaults. When the amount of information is large, investors will become overconfident and tend to believe their own judgment. At this time, in fact, the herd effect is "Pseudo-herding behavior". However, when the amount of information is small, investors become cautious and tend to make decisions based on previous investors’ behavior. At this time, the rational herd effect conveys useful information.

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