The effect of images of Michelle Obama's face on trick-or-treaters' dietary choices: A randomized control trial.

Objective: To evaluate the microfoundations of a personality-inspired public health campaign's influence on minors.

Design: Multi-year randomized control trial.

Setting: Economics professor's front porch in New Haven, CT.

Identification of Homophily and Preferential Recruitment in Respondent-Driven Sampling.

Respondent-driven sampling (RDS) is a link-tracing procedure used in epidemiologic research on hidden or hard-to-reach populations in which subjects recruit others via their social networks. Estimates from RDS studies may have poor statistical properties due to statistical dependence in sampled subjects' traits. Two distinct mechanisms account for dependence in an RDS study: homophily, the tendency for individuals to share social ties with others exhibiting similar characteristics, and preferential recruitment, in which recruiters do not recruit uniformly at random from their network alters.

Driving fatalities on US presidential election days: a reanalysis.

Background: Redelmeier and Tibshirani reported a statistical analysis in the Journal of the American Medical Association in 2008 indicating that presidential election days are strongly associated (P < 0.001) with an increased risk of driving fatalities (as measured by the number of persons involved in fatal crashes).

Findings: We present evidence indicating that the risk of driving fatalities on presidential election days is neither statistically nor substantively unusual.

Chocolate scents and product sales: a randomized controlled trial in a Canadian bookstore and café.

We report the results of a 31-day trial on the effects of chocolate scent on purchasing behavior in a bookstore. Our study replicates and extends a 10-day randomized controlled trial in order to examine the generalizability of the original finding. We first introduce the study of store atmospherics and highlight the importance and dearth of replication in this area.

Changing climates of conflict: A social network experiment in 56 schools.

Theories of human behavior suggest that individuals attend to the behavior of certain people in their community to understand what is socially normative and adjust their own behavior in response. An experiment tested these theories by randomizing an anticonflict intervention across 56 schools with 24,191 students. After comprehensively measuring every school's social network, randomly selected seed groups of 20-32 students from randomly selected schools were assigned to an intervention that encouraged their public stance against conflict at school.

Editorial Bias in Crowd-Sourced Political Information.

The Internet has dramatically expanded citizens' access to and ability to engage with political information. On many websites, any user can contribute and edit "crowd-sourced" information about important political figures. One of the most prominent examples of crowd-sourced information on the Internet is Wikipedia, a free and open encyclopedia created and edited entirely by users, and one of the world's most accessed websites.

Nonparametric Identification for Respondent-Driven Sampling.

We detail nonparametric identification results for respondent-driven sampling when sampling probabilities are assumed to be functions of network degree known to scale. We show that the conditions for consistency of the Volz-Heckathorn estimator are weaker than previously assumed.

Combining List Experiment and Direct Question Estimates of Sensitive Behavior Prevalence.

Survey respondents may give untruthful answers to sensitive questions when asked directly. In recent years, researchers have turned to the list experiment (also known as the item count technique) to overcome this difficulty. While list experiments are arguably less prone to bias than direct questioning, list experiments are also more susceptible to sampling variability.