What is a model evaluation metric?

A model evaluation metric is fundamentally a quantitative measure that is used to assess the performance of a machine learning model. This means it provides numerical values that help to determine how well the model performs in terms of accuracy, precision, recall, F1 score, or other relevant metrics depending on the context and purpose of the model.

Using quantitative metrics allows practitioners to compare different models or evaluate the impact of changes made to an existing model. For instance, during the model training process, evaluation metrics can help to guide decisions about tuning hyperparameters or selecting features, thereby enabling the model to achieve better performance.

In contrast, qualitative analyses might provide insights into model performance based on human judgment or descriptive statistics, but they lack the objectivity and reproducibility associated with quantitative measures. Methods for selecting training data pertain to the data preparation stage rather than model evaluation, and tools for visualizing model outputs serve a different purpose, focusing more on interpretation rather than assessment. Thus, understanding model evaluation metrics is crucial for developing and refining effective machine learning models.