本文所探討的產業比價效應與羊群效應相似，羊群效應是行為財務學中的一個重要內容，與效率市場相反，當投資人產生不理性的跟風買入賣出時，行為財務學家便以動物界中的羊群效應對其進行描述。中國證券市場仍屬發展階段，政策干預頻繁，且投資主體以散戶為主，缺乏專業投資技能與投資判斷。
與羊群效應研究對象為個股報酬率和大盤報酬率之間的偏離程度不同，比價效應的研究對象是個股報酬率和產業報酬率之間的偏離程度，本文選取了中國大陸股票市場疫情前後六年時間裡成交金額前九大的產業，以CSAD模型為基礎，並加入考量新冠疫情的虛擬變數，以此來探究疫情前後中國大陸股票市場比價效應的變化。
實證結果顯示，除批發零售業完全不存在比價效應，和製造業僅在疫情後下跌市場存在比價效應外，比價效應在其餘七大產業中普遍存在，其中又以金融業較爲特殊，是唯一在全時期、疫情前和疫情後三個階段的上漲市場存在比價效應的產業。
最後，本文根據實證模型的發現，給予政府當局和投資人相關的政策與投資建議。

The industry Price Comparability Effect discussed in this article is similar to the herd effect, which is an important aspect of behavioral finance. In contrast to efficient markets, when investors engage in irrational buying and selling following the trend, behavioral finance experts describe it as the herd effect in the animal kingdom. The Chinese securities market is still in the development stage, with frequent policy interventions and a focus on individual investors, lacking professional investment skills and judgment.
Different from the herd effect, which focuses on the average return rate of the market, the Price Comparability Effect focuses on the average return rate of various industries. This paper selects the top nine industries with the largest transaction amount in the six years before and after the epidemic in the Chinese mainland stock market. Based on the CSAD model, and adding dummy variables to consider the COVID-19, this paper explores the changes in the Price Comparability Effect of the Chinese mainland stock market before and after the epidemic.
The empirical results show that, except for the wholesale and retail industry, which has no Price Comparability Effect at all, and the manufacturing industry, which only has a Price Comparability Effect in the declining market after the epidemic, the Price Comparability Effect is common in the other seven major industries, among which the financial industry is more special and is the only industry that has a Price Comparability Effect in the rising market during the entire period and before and after the epidemic.
Finally, based on the findings of the empirical model, this article provides relevant policy and investment recommendations to government authorities and investors.

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