alex_zag_al comments on The Power of Noise - Less Wrong

28 Post author: jsteinhardt 16 June 2014 05:26PM

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Comment author: johnswentworth 20 June 2014 05:49:05AM 1 point [-]

The randomized control trial is a great example where a superintelligence actually could do better by using a non-random strategy. Ideally, an AI could take its whole prior into account and do a value of information calculation. Even if it had no useful prior, that would just mean that any method of choosing is equally "random" under the the AI's knowledge.

Comment author: alex_zag_al 14 November 2015 09:39:19AM *  2 points [-]

Bayesian adaptive clinical trial designs place subjects in treatment groups based on a posterior distribution. (Clinical trials accrue patients gradually, so you don't have to assign the patients using the prior: you assign new patients using the posterior conditioned on observations of the current patients.)

These adaptive trials are, as you conjecture, much more efficient than traditional randomized trials.

Example: I-SPY 2. Assigns patients to treatments based on their "biomarkers" (biological measurements made on the patients) and the posterior derived from previous patients.

When I heard one of the authors explain adaptive trials in a talk, he said they were based on multi-armed bandit theory, with a utility function that combines accuracy of results with welfare of the patients in the trial.

However, unlike in conventional multi-armed bandit theory, the trial design still makes random decisions! The trials are still sort of randomized: "adaptively randomized," with patients having a higher chance of being assigned to certain groups than others, based on the current posterior distribution.