What is the test for drawing an inference from a failure to produce evidence?

"The better practice ... is for the party seeking to obtain a charge encompassing such an inference to advise the trial judge and counsel out of the presence of the jury, at the close of his opponent's case, of his intent to so request and demonstrating the names or classes of available persons not called and the reasons for the conclusion that they have superior knowledge of the facts. This would accord the party accused of nonproduction the opportunity of either calling the designated witness or demonstrating to the court by argument or proof the reason for the failure to call. Depending upon the particular circumstances thus disclosed, the trial court may determine that the failure to call the witness raised no inference, or an unfavorable one, and hence whether any reference in the summation or a charge is warranted." (State v. Clawans (1962) 38 N.J. 162-172, 183 A.2d 77, 82.)

1 As one commentator noted, "[a] person's failure to produce evidence is ambiguous; a variety of considerations unrelated to guilt might motivate him not to put a particular witness on the stand. He may fear that the witness he calls will be impeached because of a criminal record, that the person's appearance or mannerisms will adversely impress the jury, or that the potential witness is just too unpredictable or untrustworthy to call." (Comment, Drawing an Inference from the Failure to Produce a Knowledgeable Witness: Evidentiary and Constitutional Considerations (1973) 61 Cal.L.Rev. 1422, 1427; see also United States v. Busic (3d Cir.1978) 587 F.2d 577, 586.)