Loss

Also written: loss function, loss functions

A single number saying how wrong a model's predictions are. Training tries to make it small.

Other terms from the same lesson

• absolute value: A number with its minus sign dropped: the absolute value of -3 is 3.
• Huber loss: A loss that treats small misses like squared error and big misses like absolute error, so a few wild values can't dominate training.
• mean absolute error: The average size of the misses, ignoring whether each was too high or too low. A miss twice as big costs twice as much.
• mean squared error: A loss: square each prediction's error and average them, so big mistakes count extra.
• quantile loss: A lopsided loss that charges more for misses in one direction, such as running out of stock costing more than overstocking.