NTH

Planning to Learn

AuthorsIan Osband

AffiliationsGoogle DeepMind

October 13, 2026 2 min read
Watch on YouTube
The one-line take

This paper makes classification more forward-looking by designing a loss that values not just immediate accuracy gains, but how much future learning an update enables.

Key results

2.2
ResNet-50 ImageNet top-1 gain

Percentage-point improvement over cross-entropy.

3.3
ResNet-50 gain at 10% label noise

Top-1 percentage-point improvement over cross-entropy.

7.3
ResNet-50 gain at 50% label noise

Top-1 percentage-point improvement over cross-entropy.

1.364
ResNet-50 test NLL with horizon cross-entropy

Reduced from 1.467 under standard cross-entropy.

What the paper found

Planning to Learn treats training as a finite-budget allocation problem: each update should favor examples that can still improve before training ends. The paper introduces a horizon loss, defined by averaging future classification error over the remaining learning horizon, with that horizon estimated from the learning rates still to come. Its per-example gradient weight interpolates between exact policy gradient at zero horizon and cross-entropy at an effectively unlimited horizon. This lets the method shift from broad learning early to deprioritizing examples that are unlikely to become correct late in training. On ImageNet, it improves top-1 accuracy over cross-entropy by 1.0–2.4 percentage points across ResNet-50, ResNet-101, and ViT-S/16; on ResNet-50, the gain is 2.2 points. The advantage grows with label noise: the ResNet-50 gain rises from 3.3 points at 10% noise to 7.3 points at 50% noise. The paper also plans cross-entropy itself, lowering ResNet-50 test negative log-likelihood from 1.467 to 1.364. The framing connects finite-horizon allocation to policy-gradient LLM post-training, citing OpenAI’s reasoning work and DeepSeek-R1, although the experiments are in image classification.

Original abstract

Policy-gradient methods are central to modern reinforcement learning, including LLM post-training. When they struggle, the usual suspects are exploration, credit assignment and action-sampling noise. Classification has none of them. A classifier is a policy whose expected reward, its \emph{expected accuracy}, is the probability it assigns to the correct label, and because that label is known, the policy gradient is exact and smooth. Yet exact policy gradient loses to cross-entropy, even on expected accuracy. The exact gradient is myopic: it values an update only by what it buys now, but each update also sets where the next one starts, so an update's value depends on how much learning remains. Viewed this way, cross-entropy is patient accuracy, the total error an example would pay if its log-odds rose at unit speed forever, while exact policy gradient is the zero-horizon limit. Truncating this total at the learning that remains yields the horizon loss, a one-line change that moves from cross-entropy toward exact policy gradient as training runs out. In a simple allocation model, it provably escapes the trap that catches each endpoint. On MNIST and on ImageNet with ResNet-50, ResNet-101 and ViT-S/16, the horizon loss improves top-1 accuracy over cross-entropy at a flat learning rate, and the gain grows with label noise.

Read the original paper

More in Optimization

Browse all 39 papers →