Accelerometer Data (Beiwe)

Accelerometer data obtained by the Beiwe mobile app. For each participant who produced accelerometer data on their smartphone, a file is generated containing daily accelerometer magnitude features for each day during the study. Magnitude is defined by the square root of the sum of squared x, y, and z-axis acceleration values. The unit of acceleration is gravity, or 9.8 meters per squared second. Raw data is available upon request however extremely large. The features computed are:

1) acc.mag.mean/sd/min/max/rmssd: mean, standard deviation, minimum, maximum, and root mean square of the successive differences of the raw acceleration magnitude recorded during a 24-hour day;
2) acc.still: the proportion of raw magnitude values that are between 0.995 and 1.005, indicating a lack of movement (hence "still") of the smartphone;
3) acc.complete: the percentage of the day accelerometer data is produced; when this value is low (e.g. <0.2), the features computed are not representative of the whole day and should not be treated as reliable.