A new study from Georgia Tech and Yahoo Labs researchers shows that weather and demographics play a significant role in determining how positively or negatively someone will review a restaurant online. In short, bad weather equals negative reviews. Saeideh Bakhshi (a Yahoo Labs intern and Georgia Tech PhD candidate), Partha Kanuparthy (a Yahoo Labs scientist who was a student at Georgia Tech while conducting the research), and Georgia Tech professor Eric Gilbert, co-authored the study which will be presented at the 23rd International World Wide Web Conference in Seoul, South Korea on April 10. The Georgia Tech team analyzed data from Foursquare, Citysearch, and TripAdvisor, including 840 thousand restaurants and their 1.1 million associated reviews from 2002 to 2011, spread across every U.S. state. They found that "while endogenous factors such as restaurant attributes (e.g., meal, price, service) affect recommendations, surprisingly, exogenous factors such as demographics (e.g., neighborhood diversity, education) and weather (e.g., temperature, rain, snow, season) also exert a significant effect on reviews." Restaurant reviews written while the temperature is between 70◦ F and 100◦ F tend to be the most positive. Reviews written in temperatures below 40◦ F and above 100◦ F tend to be more negative. Additionally, reviews are more negative when it is raining or snowing. The authors' research also finds that demographics surrounding a restaurant are perhaps as influential as the weather. In more racially diverse neighborhoods and/or in those with residents who have college-level education, the average restaurant rating is higher. The study is the first to look at exogenous factors and how they relate to online restaurant reviews. The work carries possible implications for designing online recommendation sites and for restaurants in general. You can read the full paper, "Demographics, Weather and Online Reviews: A Study of Restaurant Recommendations," on our website here.