Burdens of Production and Persuasion

and

Shifting Burdens

    It is possible to visualize the burdens of proof at trial and the judge-jury respective areas of responsibility in diagram form.  The basic set-up looks like this:

Please keep in mind that this diagram is not drawn to any sort of scale.  I intend it only to give a quick visual representation of the relationship of the judge's and jury's functions.  As a practical matter, we should realize that the zone of rationality (Zones B and C above) is extraordinarily wide, and the areas in which we leave the decision to the court (Zones A and D) are quite narrow.   That is because 700 years of common law history and 200 years of the Seventh Amendment tell us that the jury should make the decision whenever reasonable people might disagree.  With respect to burdens of production and persuasion at trial, the needle begins on the left because the plaintiff has both burdens. 

The blue area represents what I call the "zone of rationality"—the zone within which a reasonable jury could find for either side.  Remember that it is the jury's job to "place" the needle within the zone of rationality; the needle is at no particular location within the zone of rationality until the jury puts it somewhere.  The white areas on either side are the areas in which the judge will grant summary judgment pursuant to Rule 56 or judgment as a matter of law pursuant to Rule 50.  If the judge can see the needle (and the party who appears to be losing has had a chance to present evidence), the case ends with a ruling from the bench.  Remember the "statement" that the court is making if it takes the case away from the jury:  that taking all of the evidence in the light most favorable to the party against whom the court is ruling, no rational jury could find for that party. 

This diagram also represents the relationships of the two burdens of proof that we have discussed.  The solid lines that define the zone of rationality also represent the parties' respective burdens of production (burdens of coming forward).  If the plaintiff fails to get the needle into the zone of rationality (i.e. across the A-B line), he fails to carry his burden of production and will lose either a summary judgment or a judgment as a matter of law, depending on the stage at which the case is.  Although the defendant has no formal burden of production with respect to the elements of the plaintiff's cause of action, as a practical matter he may acquire one if the plaintiff's proof is so strong that the needle reappears to the right of the zone of rationality, in Zone D. 

The dotted line represents the plaintiff's burden of persuasion.  It is difficult to see on the chart; I deliberately made it so to remind us that the court cannot perceive anything that is within the blue zone.  That is the jury's area, and the court may not intrude.  (I realize the irony of saying that the court cannot perceive anything that is within the zone of rationality, but I retreat not one inch from the assertion.)

Thus, as a functional matter, the court can only decide the case while the needle resides in Zones A or D.  If the needle is not visible to the court, then the case goes to the jury, even though the court may have its own idea of where within Zones B and C it would place the needle were that its right.