Will see the Importance, why, and when we use Recall and Precision.
Recall
Recall is important when you want to minimize the number of false negatives, even if it means increasing the number of false positives. Some examples of situations where recall might be important include:
- Medical diagnosis: False negatives (patients who are misdiagnosed as healthy) can have serious consequences, so it is important to minimize the number of false negatives even if it means increasing the number of false positives (patients who are unnecessarily treated).
- Fraud detection: False negatives (fraudulent transactions that are missed) can be costly, so it is important to minimize the number of false negatives even if it means increasing the number of false positives (legitimate transactions that are flagged as fraudulent).
- Spam filtering: False negatives (spam emails that get through) can be annoying and disruptive, so it is important to minimize the number of false negatives even if it means increasing the number of false positives (legitimate emails that are marked as spam).
- Security: False negatives (intrusions that are not detected) can have serious consequences, so it is important to minimize the number of false negatives even if it means increasing the number of false positives (legitimate activities that are flagged as suspicious).
Precision
Precision is important when you want to minimize the number of false positives, even if it means increasing the number of false negatives. Some examples of situations where precision might be important include:
- Medical treatment: False positives (patients who are unnecessarily treated) can have serious consequences, so it is important to minimize the number of false positives even if it means increasing the number of false negatives (patients who are misdiagnosed as healthy).
- Spam filtering: False positives (legitimate emails that are marked as spam) can be annoying and disruptive, so it is important to minimize the number of false positives even if it means increasing the number of false negatives (spam emails that get through).
- Advertising: False positives (customers who are shown irrelevant ads) can be annoying and lead to a poor user experience, so it is important to minimize the number of false positives even if it means increasing the number of false negatives (customers who are not shown relevant ads).
- Search engines: False positives (irrelevant search results) can be frustrating for users, so it is important to minimize the number of false positives even if it means increasing the number of false negatives (relevant search results that are missed).
Accuracy
Accuracy is a good overall measure of the model’s performance, and it is appropriate to use when the classes are balanced (i.e., there are approximately equal numbers of positive and negative cases). The F1 score is a good overall measure of the model’s performance that takes into account both precision and recall. It is a good choice when you want to balance precision and recall and when you want to use a single metric that takes both into account.
Here are some examples of situations where accuracy and/or the F1 score might be important:
- Customer service: You want to know how often the model is correct overall and you want to balance precision (minimizing the number of false negatives) and recall (minimizing the number of false positives) in order to provide the best possible customer service.
- Medical diagnosis: You want to know how often the model is correct overall and you want to balance precision (minimizing the number of false positives) and recall (minimizing the number of false negatives) in order to provide the best possible care to patients.
- Spam filtering: You want to know how often the model is correct overall and you want to balance precision (minimizing the number of false positives) and recall (minimizing the number of false negatives) in order to provide the best possible user experience.
- Search engines: You want to know how often the model is correct overall and you want to balance precision (minimizing the number of false positives) and recall (minimizing the number of false negatives) in order to provide the best possible search results.