The presence or absence of both procedures was randomly assigned to 34 civil and 33 criminal trials in Wisconsin circuit courts. Following the trials, 63 judges, 95 attorneys, and 550 jurors completed questionnaires. Findings did not support the hypotheses that written instructions would help the jurors recall the judge's instructions, increase the jurors' satisfaction, or shorten the trial. However, the written copy did appear to reduce disputes among jurors about the judge's instructions. In addition, they did not appear to reduce or increase the time involved in deliberations and did not place excessive demands on court resources. Findings also did not support the hypotheses that preliminary instructions would aid recall, would reduce juror confusion, would be impractical, or would place excessive demands on the judge. However, findings showed that preliminary instructions helped the jurors follow legal guidelines in their decisionmaking and increased satisfaction with the trial process. Footnotes, tables, and 20 references. (Author abstract modified)