Participants were 99 undergraduate males who took part in the experiment as part of their psychology course. Another group of 57 males and 67 females served as observers. The four levels of trial procedure were single investigator procedure, double investigator procedure, assigned adversary procedure, and choice adversary procedure. The procedures incorporated the three essential differences between the adversary and inquisitorial models: two attorneys rather than one, attorney alignment with the defendant, and choice of attorney. All three factors were required to produce a significant increment in defendants' procedural satisfaction compared to the single investigator model. All three factors were also necessary to produce a significant increment in subjects' satisfaction with guilty verdicts. Only the number of attorneys produced a significant increase in observers' satisfaction with the procedure. Innocent verdicts produced more favorable procedure and verdict evaluations. Opportunity for evidence presentation appears to be a likely mediator of the impact of procedural variations on both participants' and observers' judgments. One reference note and 29 references are provided. (Author abstract modified)