This document summarizes a study examining how Fear of Missing Out (FoMO) predicts compulsive mobile phone use in social situations. The study measured FoMO, frequency of phone checking, habitual checking behavior, and problematic mobile phone use when alone and in company. Regression analysis found FoMO was a strong predictor of problematic phone use for both men and women. FoMO led to higher levels of problematic use, though the effect was stronger for men. The study suggests FoMO and social norms both influence how often people check their phones in social situations.