BLEU vs ROUGE: BLEU measures precision of n-grams, ROUGE measures recall

MAP (mean average precision) measures: area under the precision-recall curve averaged across queries

MAP measures the area under the precision-recall curve averaged across queries

the mel scale is: a nonlinear frequency scale that models human pitch perception

Mel scale: a nonlinear frequency scale modeling human pitch perception

word error rate (WER) measures: edit distance between predicted and reference transcriptions

Word Error Rate (WER) measures the edit distance between predicted and reference transcriptions

L1 vs L2 regularization: L1 gives sparsity (feature selection), L2 gives small weights

L1 regularization: L1 = L2 + sparsity; L2 regularization: L2 = L1 + small weights

Brier score

Brier score measures mean squared error of probability predictions

to normalize features: when features have different scales and you use distance-based methods

Normalize features when they have different scales for distance-based methods