Table 4.
Summary of system extensions and changes in performance compared to the original shared task systems
| Team | Subtask (evaluation metric) | Extension description | Score | Performance change |
|---|---|---|---|---|
| NRC-Canada | 1 (ADR F1-score) | Ensemble of 7 classifiers with random undersampling of the majority class to imbalance ratio of 1: 2 | 0.456 | +0.021 |
| UKNLP | 1 (ADR F1-score) | Additional training data, logistic regression and CNN ensembles | 0.459 | +0.057 |
| InfyNLP | 2 (micro-averaged F1-score for classes 1 and 2) | Additional training data, increased number of random search runs | 0.692 | −0.001 |
| NRC-Canada | 2 (micro-averaged F1-score for classes 1 and 2) | Additional training data | 0.679 | +0.0058 |
| UKNLP | 2 (micro-averaged F1-score for classes 1 and 2) | Additional training data (and removed all non-ASCII characters from tweets) | 0.694 | +0.005 |
| TurkuNLP | 2 (micro-averaged F1-score for classes 1 and 2) | Additional training data | 0.665 | +0.002 |
| UKNLP | 3 (accuracy) | CNN instead of LSTM at the character level for hierarchical composition | 87.7% | +0.5 |