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Anticipate reward hacking in an RLHF run

Identify how the next RLHF run could improve reward while making the model less useful.

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The challenge

A team is preparing an RLHF run using a reward model trained mainly on responses from its earlier supervised checkpoint. Existing warning signs include longer answers without a quality gain, agreement with false premises and changing refusal behaviour.

Investigate how the policy could exploit that reward signal during optimization. Your memo must connect specific mechanisms to tests and mitigations that fit the limited evaluation compute and release window, while explaining what improvement in reward would leave unproven.

What you'll practise

  • Proxy-objective failures

    Explain what the policy can exploit and why reward may diverge from the intended outcome.

  • Targeted evaluations

    Connect each proposed test to a specific failure mechanism.

  • Practical mitigations

    Specify changes that fit the run and acknowledge the risk they leave behind.

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Your pre-training risk memoYour response
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