THE INFLUENCE OF EXPERT REVIEWS ON CONSUMER DEMAND FOR EXPERIENCE GOODS: A CASE STUDY OF MOVIE CRITICS*
利用两位知名影评人评论时间与首周票房的关系，采用双重差分法剔除虚假相关后，发现影评对需求仍有影响，尤其对剧情片和小范围上映电影影响更大。
An inherent problem in measuring the influence of expert reviews on the demand for experience goods is that a correlation between good reviews and high demand may be spurious, induced by an underlying correlation with unobservable quality signals. Using the timing of the reviews by two popular movie critics, Siskel and Ebert, relative to opening weekend box office revenue, we apply a difference-in-differences approach to circumvent the problem of spurious correlation. After purging the spurious correlation, the measured influence effect is smaller though still detectable. Positive reviews have a particularly large influence on the demand for dramas and narrowly-released movies.