difficulty

Definition

How hard an item is, treated as something to measure and then exploit. It underpins curriculum learning, where examples are ordered easy to hard, and it matters more still in RL on verifiable tasks: problems the model always solves give no gradient, and problems it never solves give no reward. The useful data sits at the boundary, so difficulty estimation becomes a data-selection technique rather than a description.

Explainers using this term

• Diagnosing Broken Training — Telling Divergence, NaN, and Plateaus ApartOn the difficulty of training Recurrent Neural Networks
• Weight Initialization and Regularization — What Lets Training Start, and What Keeps It GoingUnderstanding the Difficulty of Training Deep Feedforward Neural Networks