Effective Preprocessing and Normalization Techniques for COVID-19 Twitter Streams with POS Tagging via Lightweight Hidden Markov Model

Table 5

Evaluation of OOV words and F1 score.

OOV operations	Precision	Recall	F1 score
Insertion	0.872	0.801	0.834993
Deletion	0.857	0.782	0.817784
Substitution	0.839	0.768	0.801932
Tokenization	0.894	0.852	0.872495