7-days of valid data). Using only dates from the log and the Choi algorithm yielded: 1) larger samples with valid data than using log dates and times, 2) similar wear-times as using log dates and times, 3) more wear-time (V, 48.1 min more; VM, 29.5 min more) than only log dates and Troiano algorithm. Wear-time algorithm impacted sedentary time (~30-60 min lower for Troiano vs. Choi) but not moderate-to-vigorous (MV) PA time. Using V-axis cut-points yielded ~60 min more sedentary time and ~10 min less MVPA time than using VM cut-points. Conclusions Combining log-dates and the Choi algorithm was optimal, minimizing missing data and researcher burden. Estimates of time in physical activity and sedentary behavior are not directly comparable between V-axis and VM cut-points. These findings will inform consensus development for accelerometer data processing in ongoing epidemiologic studies."/>
Skip to main content

Table 1 Description of missing data in participant monitor-logs: Women’s Health Study

From: Impact of accelerometer data processing decisions on the sample size, wear time and physical activity level of a large cohort study

Day Any missing
  Date N (%) Time N (%) AM or PM N (%)
One 2 (0.0) 107 (1.4) 1475 (19.3)
Two 51 (0.7) 157 (2.1) 1560 (20.4)
Three 66 (0.9) 209 (2.7) 1603 (21.0)
Four 79 (1.0) 264 (3.5) 1698 (22.2)
Five 102 (1.3) 297 (3.9) 1736 (22.7)
Six 120 (1.6) 320 (4.2) 1760 (23.0)
Seven 167 (2.2) 329 (4.3) 1788 (23.4)
  1. Note: Date refers to missing month, day or year for a given day; Time refers to missing hour and/or minute for either the time the monitor was put on or the time the monitor was taken off; AM or PM refers to missing AM/PM for either the time the monitor was put on or the time the monitor was taken off.