# CoNTACT
### Model description
Contextual Neural Transformer Adapted to COVID-19 Tweets or **CoNTACT** is a Dutch RobBERT model (```pdelobelle/robbert-v2-dutch-base```) adapted to the domain of COVID-19 tweets. The model was developed at [CLiPS](https://www.uantwerpen.be/en/research-groups/clips/) by Jens Lemmens, Jens Van Nooten, Tim Kreutz and Walter Daelemans. A full description of the model, the data that was used and the experiments that were conducted can be found in this ArXiv preprint: https://arxiv.org/abs/2203.07362
### Intended use
The model was developed with the intention of achieving high results on NLP tasks involving Dutch social media messages related to COVID-19.
### How to use
CoNTACT should be fine-tuned on a downstream task. This can be achieved by referring to ```clips/contact``` in the '--model\_name\_or\_path' argument in Huggingface/Transformers' example scripts, or by loading CoNTACT (as shown below) and fine-tuning it using your own code:
```
from transformers import AutoModel, AutoTokenizer
model = AutoModel.from_pretrained('clips/contact')
tokenizer = AutoTokenizer.from_pretrained('clips/contact')
...
```
### Training data
CoNTACT was trained on 2.8M Dutch tweets related to COVID-19 that were posted in 2021.
### Training Procedure
The model's pre-training phase was extended by performing Masked Language Modeling (MLM) on the training data described above. This was done for 4 epochs, using the largest possible batch size that fit working memory (32).
### Evaluation
The model was evaluated on two tasks using data from two social media platforms: Twitter and Facebook. Task 1 involved the binary classification of COVID-19 vaccine stance (hesitant vs. not hesitant), whereas task 2 consisted of the mulilabel, multiclass classification of arguments for vaccine hesitancy. CoNTACT outperformed out-of-the-box RobBERT in virtually all our experiments, and with statistical significance in most cases.
### How to cite
```
@misc{lemmens2022contact,
title={CoNTACT: A Dutch COVID-19 Adapted BERT for Vaccine Hesitancy and Argumentation Detection},
author={Jens Lemmens and Jens Van Nooten and Tim Kreutz and Walter Daelemans},
year={2022},
eprint={2203.07362},
archivePrefix={arXiv},
primaryClass={cs.CL}
}
```