All profiles were evaluated by one of three trained coders using our research codebook. We have used this codebook in previous work evaluating displayed alcohol references on SNS profiles.19, 24 The coders viewed publicly accessible elements of the Facebook profile including the wall, tagged pictures, profile pictures and bumper stickers in order to determine whether alcohol references were present. One year of profile data was assessed, starting from the date of evaluation and going back to the same date one year prior. A 20% random subsample of profiles were evaluated by all three coders to test interrater reliability. Cohen’s Kappa statistic was used to evaluate the extent to which there was overall agreement in the coding of the presence or absence of alcohol references on a Moreno et al