0795 IMPORTANCE OF SLEEP DATA IN PREDICTING 
NEXT-DAY STRESS, HAPPINESS, AND HEALTH IN COLLEGE STUDENTS

Abstract Introduction: Perceived wellbeing, as measured by self-reported health, stress, and happiness, has a number of important clinical health consequences. The ability to model and predict these measures could therefore be immensely beneficial in the treatment and prevention of mental illness. However, predicting self-reported health, stress, and happiness is a difficult problem often requiring large, multi-modal datasets. We show that the accuracy for predicting next-day wellbeing is improved when including simple sleep features. Methods: Data from 144 college students were collected during a 30-day study. Participants wore two sensors to collect actigraphy and physiology data, installed a data logger on their smartphone, and filled out online surveys. Participants self-reported daily on three wellbeing measures (stress - calm; sad - happy; sick - healthy) using a visual analog scale (later scored 0 to 100). The top and bottom 40% of scores were assigned positive and negative labels, respectively. A hierarchical bayes machine learning algorithm was trained to predict each next-day wellbeing label on two data sets: (1) including self-reported sleep features (e.g., self-reported sleep latency, bedtime, and wake time), and (2) discarding sleep features. Both data sets include approximately 20 features computed from wearable sensors, phone, and online surveys. In total, 2,769 days of data were used. Results: Without including the sleep features, hold-out test accuracies for stress, happiness, and healthy were 79.62%, 78.24%, 83.55%, respectively. When including sleep features, the accuracies were improved for the stress and happy predictions to 80.67%, 80.40%, respectively; however the healthy prediction accuracy worsened slightly to 83.12%. Using McNemar’s test we find that including sleep features does not significantly improve the classifiers for the stress or healthy prediction, but does significantly improve the classifier for the happy prediction (p