Majority baseline

The accuracy you get by always predicting the most common class. A model has to beat it to be worth anything.

Other terms from the same lesson

• confusion matrix: A table counting a classifier's predictions against the true answers: one row per true class, one column per predicted class. For yes/no it shows true and false positives and negatives.
• multiclass classification: Classification with more than two possible answers, such as sorting customers by their favorite product category.
• softmax regression: Logistic regression for more than two classes: one score per class, turned into probabilities by softmax.