Table 5 Model fit indices of the stationary, linear and breakpoint model for each of the four forum-level outcome measures
Outcome measure | Model | Evaluation metric | |||
|---|---|---|---|---|---|
AIC | BIC | MAE | RMSE | ||
Forum activity (number of posts) | Stationary model | 3088.85 | 3094.98 | 3207.95 | 4201.70 |
Linear model | 3029.02 | 3038.39 | 2821.48 | 3456.99 | |
Breakpoint model (5) | 2814.08 | 2835.25 | 1278.11 | 1706.29 | |
Number of words per post | Stationary model | 1045.71 | 1051.84 | 5.37 | 6.54 |
Linear model | 994.55 | 1003.74 | 4.38 | 5.53 | |
Breakpoint model (4) | 917.95 | 936.32 | 3.24 | 4.25 | |
Proportion posts with extremist language | Stationary model | − 766.05 | − 759.92 | 0.0260 | 0.0212 |
Linear model | − 834.57 | − 825.38 | 0.0139 | 0.0169 | |
Breakpoint model (4) | − 1013.08 | − 994.71 | 0.0073 | 0.0094 | |
Average extremist language score per post | Stationary model | 253.29 | 259.42 | 0.4483 | 0.5326 |
Linear model | 252.95 | 262.14 | 0.4357 | 0.5286 | |
Breakpoint model (3) | 115.50 | 130.81 | 0.2510 | 0.3379 |