NLP involves different types of tasks, such as classification, generation, and extraction. Depending on the task, you may need different metrics to measure the accuracy of your NLP model. For example, for classification tasks, such as sentiment analysis or spam detection, you may use metrics such as accuracy, precision, recall, and F1-score. These metrics compare the predicted labels with the true labels and calculate the proportion of correct predictions, relevant predictions, retrieved items, and balanced performance. For generation tasks, such as machine translation or text summarization, you may use metrics such as BLEU, ROUGE, and METEOR. These metrics compare the generated text with one or more reference texts and calculate the similarity based on n-grams, word order, and semantics. For extraction tasks, such as named entity recognition or relation extraction, you may use metrics such as precision, recall, and F1-score at the entity or relation level, as well as metrics such as span accuracy and slot error rate at the token level.