Darcy Ummels

The validation of a pocket worn activity tracker | 103 5 Table 5.3 Descriptive statistics, Pearson correlation coefficient and paired sample t ‐ test of step count by the MOX MissActivity compared to the video observations in comparison with reference applications. Activity tracker Difference in step counta, mean (95% CI) Percentage error, mean (95% CI) Absolute percentage error, mean (95% CI) Limits of agreement (lower bound– upper bound) Pearson correlation coefficient p ‐ value Smallest detectable change (steps) MOX MissActivity 13 ( − 19 to 45) 2.6 ( − 2.6 to 7.4) 9.3 (7.3 to 11.3) − 116 to 142 0.88 0.40 129 activPAL c 238 (198 to 277) 38.1 (33.0 to 43.1) 38.1 (33.0 to 43.1) 97 to 378 0.75 > .001 485 Fitbit c − 160 ( − 287 to − 35) − 20.0 ( − 38.3 to − 1.9) 31.3 (19.6 to 43.0) − 556 to 290 0.77 .16 522 a Video observation minus activity tracker; b One missing value for step count in the MOX MissActivity (1/20, 5%); c Five missing values for step count in the activPAL and Fitbit (5/20, 25%). Table 5.4 Descriptive statistics, Pearson correlation coefficient and paired sample t ‐ test of dynamic, standing, and sedentary time by MOX MissActivity compared to the video observations in comparison with reference applications without outliers. Behavior Difference in behavior in seconds a , mean (95% CI) Percentage error, mean (95% CI) Absolute percentage error, mean (95% CI) Limits of agreement (lower bound– upper bound) Pearson correlation coefficient p ‐ value Smallest detectable change (in seconds) MOX MissActivity Dynamic 20 ( − 35 to 74) 4.8 ( − 6.7 to 16.2) 15.9 (7.5 to 24.3) − 197 to 237 0.55 0.513 215 MOX MissActivity Standing − 25 ( − 149 to 99) 0.7 ( − 16.5 to 17.9) 19.9 (6.0 to 33.7) − 515 to 460 0.91 0.113 488 MOX MissActivity Sedentary 87 ( − 46 to 221) 5.0 ( − 2.6 to 12.8) 9.6 (3.0 to 16.0) − 441 to 616 0.92 0.845 538 MOX Annegarn Dynamic 273 (236 to 309) 63.6 (59.0 to 68.3) 63.6 (59.0 to 68.3) 127 to 410 0.36 0.000 552 MOX Annegarn Standing − 255 ( − 398 to − 112) − 34.3 ( − 54.3 to − 14.4) 45.5 (32.7 to 58.3) − 1105 to 474 0.65 0.004 743 MOX Annegarn Sedentary 64 ( − 88 to 215) 3.9 ( − 4.7 to 12.4) 10.3 (3.3 to 17.4) − 675 to 941 0.85 0.191 599 activPAL Dynamic b 133 (89 to 176) 30.2 (21.2 to 39.1) 30.1 (21.3 to 39.0) − 17 to 283 0.52 0.001 148 activPAL Standing b − 519 ( − 873 to − 166) − 69.9 ( − 117.7 to − 22.1) 74.6 (29.5 to 119.8) − 1720 to 692 0.51 0.004 1745 activPAL Sedentary b 449 (92 to 807) 22.4 (5.8 to 39.0) 22.4 (5.8 to 39.0) − 905 to 1804 0.29 0.001 1638 Fitbit Dynamic b 347 (226 to 467) 81.8 (53.0 to 110.7) 96.6 (85.0 to 108.5) − 2854 to 555.7 0.05 0.000 832 a Video observations minus activity tracker; b Five (5/20 25%) missing values for the activPAL and Fitbit.