本文利用豐田RAV4車頂漏水事件作爲自然實驗，研究使用者生成內容對相關銷售的影響。透過差異中差異計量方法，我們的實證結果顯示，車頂漏水事件的使用者生成內容導致豐田RAV4的銷售下降超過30%。但是，估計結果可能不僅捕捉到處理效果，還捕捉到銷售的其他均衡效應。因此，我們估計了一個結構化需求模型，並進行了反事實模擬，顯示失去的銷售約爲9,000輛，相當於上一年總銷量的25%。而另一款同品牌的新車推出僅對RAV4的銷售造成大約4%的下降。

This paper studies the effects of user-generated content on relative sales by exploiting the Toyota RAV4 roof leak incident as a natural experiment. Using a reduced-form difference-in-differences approach, our empirical results show that user-generated content from the roof leak incident caused sales of the Toyota RAV4 to fall by more than 30%. However, the estimates may capture not only the treatment effects but also other equilibrium effects on sales. Therefore, we estimate a structural nested logit demand model, and conduct counterfactual simulations showing that lost sales were approximately 9,000, equivalent to 25% of the total sales in the previous year. Cannibalization effects from Toyota Corolla Cross only led to an around 4% decrease in RAV4’s sales.