A hat-tip goes to Rob Hilsen for pointing out “The Value of Quality”, a recent study out of USC’s Marshall School of Business which looked at the business impact of positive and negative product reviews, including 421 reviews from Walt Mossberg, a technology writer at the Wall St. Journal.

Rob writes “The analysis of Mossberg’s product reviews provides powerful statistical validation that positive and negative product reviews can have real, market-moving, business impact. I missed this article when it was published late last year; however, a colleague sent it to me today and it’s worth sharing: The research showed that – on average – a positive review added 10 percent to a company’s stock value the day after Mossberg’s review is published; in addition, a company’s market value drops by 5% the day after a negative review.”

A video interview of Professor Tellis discussing “The Value of Quality” is available here.