This is a guest post by Nathaniel Stockham, a Ph.D. student in Neuroscience at Stanford University.
When I started my study of bipolar disorder, I spent an inordinate amount of time comparing different devices, each differing in ease of use, reliability, battery life, remote access, and cost. What eventually led me to Pebble was my need to know exactly what was being calculated.
After reviewing dozens of commercial and clinical devices, I determined the most important variables to measure and designed two algorithms to capture the most salient motion characteristics. After months of validation in collaboration with Pebble and the Stanford Wearables Lab, I am making these two algorithms available to the public to encourage the use of a standard set of measures.