Table 2.
Comparison of different missing data imputation approaches to the ground truth. 
outings/trajectories across 182 individuals from the Geolife data set were used to compare imputation approaches. 
missingness was imposed on the data set in equal intervals. For each outing, all measures not requiring a home location or routine were calculated. For each measure, the error relative to the ground truth is stated as a percent. For the stochastic approaches, TL, GL, and GLC, the mean daily measures from 100 simulations are used in relative error calculations. The final row is the average absolute error across all measures. The best performing missing data approach, TL with a Cauchy kernel and scaling parameter of 20, is highlighted. Also highlighted, LI had the largest average error
| LI | TL.1 | TL.10 | TL.20 | GL.1 | GL.10 | GL.20 | GLC.1 | GLC.10 | GLC.20 | |
|---|---|---|---|---|---|---|---|---|---|---|
| DistTraveled | –1.44 | –0.15 | –0.26 | –0.58 | 1.70 | 0.20 | 0.08 | –0.67 | –0.83 | –0.71 |
| RoG | –0.51 | 0.94 | 1.45 | 0.13 | 1.23 | 0.46 | 0.20 | 0.03 | –0.12 | 0.01 |
| MaxDiam | –0.41 | 0.25 | 0.22 | –0.19 | 1.16 | 0.36 | 0.27 | –0.11 | –0.28 | –0.09 |
| AvgFlightLen | 11.72 | –0.09 | –0.14 | –0.35 | 0.11 | 0.25 | 0.33 | 0.56 | 0.73 | 0.83 |
| StdFlightLen | 10.62 | –0.11 | –0.03 | –0.65 | 0.56 | 0.65 | 0.85 | 1.07 | 1.03 | 1.29 |
| AvgFlightDur | 22.55 | 0.55 | 0.40 | 0.47 | 0.12 | 0.62 | 0.69 | 1.51 | 1.64 | 1.73 |
| StdFlightDur | 29.56 | 2.72 | 2.10 | 2.29 | 1.50 | 2.33 | 2.25 | 3.57 | 3.18 | 3.58 |
| ProbPause | –10.01 | 5.22 | 5.36 | 3.80 | 10.26 | 7.88 | 7.05 | 5.35 | 4.66 | 4.38 |
| Avg. Error | 10.85 | 1.26 | 1.24 | 1.06 | 2.08 | 1.60 | 1.46 | 1.61 | 1.56 | 1.58 |