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When evidence with a scientific basis is offered, two fundamental questions arise. First, should it be admitted? Second, if so, how should it be assessed? There are numerous participants who might play a role in deciding these questions—the jury (on the second question only), the parties (through counsel), expert witnesses on each side, the trial court, the forces controlling the judicial system (which include, but are not limited to, the appellate courts), and the scientific establishment. In this Article, I will suggest that together, the last two—the forces controlling the judicial system and the scientific establishment—have a large role to play in determining how statistically based evidence shall be explained to, and may be used by, the jury. For this purpose, the scientific establishment includes not only statistical experts but also legal academics with an expertise in problems of inference and proof; they should assist the judicial system in devising pattern instructions to help the jury avoid well-recognized pitfalls in handling statistical evidence in certain well-defined and recurrent circumstances. Trial courts should be required to give those instructions in the prescribed circumstances, and neither the parties (themselves or their counsel) nor their experts should be allowed to say anything at variance with those instructions.