Recent advances in mobile health have produced several new models for
inferring stress from wearable sensors. But, the lack of a gold standard is a
major hurdle in making clinical use of continuous stress measurements derived
from wearable sensors. In this paper, we present a stress model (called
cStress) that has been carefully developed with attention
to every step of computational modeling including data collection, screening,
cleaning, filtering, feature computation, normalization, and model training.
More importantly, cStress was trained using data collected from a rigorous lab
study with 21 participants and validated on two independently collected data
sets — in a lab study on 26 participants and in a week-long field study
with 20 participants. In testing, the model obtains a recall of 89% and
a false positive rate of 5% on lab data. On field data, the model is
able to predict each instantaneous self-report with an accuracy of
72%.